Zarif was welcomed at the airport by his Lebanese counterpart Charbel Wehbe, said a statement by Iran’s Foreign Ministry.

In addition, to review the present situation in Lebanon in separate meetings with senior officials of the country, Zarif is also to follow up the process of providing Iran’s humanitarian aid for the Lebanese in the wake of the mega explosion which defaced the coastline of Beirut, destroying hundreds of buildings, IRNA reported.

At least 171 people were dead and more than 6,000 others were injured by the massive blast which was caused by the detonation of more than 2,000 tons of ammonium nitrate stored at a warehouse in the port city.

Dozens remain missing and some 300,000 have been made homeless by the fatal incident.

Zarif had earlier attended Lebanon’s Embassy in Tehran and signed a memorial book in the honor of the victims of the devastating blast.

French President Emmanuel Macron on Wednesday in a phone call with his Iranian counterpart Hassan Rouhani called on Iran to help solve the existing political crisis in Lebanon which mounted following the eruption of public protests in the Lebanese capital after the fatal explosion and has eventually led to the resignation of the government of Prime Minister Hasan Diab on Monday.

Given the present situation in Lebanon, President Macron invited Iran to take part in the international action group to solve the Lebanon crisis.

Welcoming the invitation, President Rouhani stressed the need to help Lebanese judiciary officials find those involved in the fatal incident.

So for many Lebanese, their greatest hope for credible answers about the blast that wrecked much of their capital may lie with outsiders: The French forensic police who have joined the probe and FBI investigators are expected to take part, The Associated Press reported.

French teams have pressed ahead at their work, sending divers into the underwater crater, taking explosives samples and preparing recommendations for both French and Lebanese magistrates. Among the French judicial police on the case are men and women who responded after the 2004 tsunami in Japan, the 2010 earthquake in Haiti, and the November 2015 and Bastille Day 2016 terror attacks in France.

The Beirut explosion lies at the crossroads of a disastrous accident and a crime scene. It still was not known what sparked the fire that ignited nearly 3,000 tons of ammonium nitrate that were stored for years in Beirut’s port next to densely populated residential areas. Documents have emerged that show the country’s top leadership and security officials were aware of the stockpile.

Search and rescue crews flew in from around the world in the immediate aftermath and found themselves looking at a scene that was both familiar and yet strangely alien.

“In an earthquake, it’s easier because we can understand … how it moves. But in this case, we didn’t have enough elements to understand what happened,” said Alberto Boanini, a member of the Italian rescue team. The team has seen its share of quakes and forest fires, but nothing quite like the port in Beirut, where he said it was hard to fathom what could level it so completely.

Many Lebanese want the probe taken out of the hands of their own government, having learned from past experience that the long-entrenched political factions, notorious for corruption, won’t allow any results damaging to their leadership to come to light. The explosion killed more than 175 people, injured at least 6,000, and left tens of thousands homeless.

Paris sent judicial police because a French architect was among the dead, and French law gives jurisdiction for an investigation if a citizen dies abroad under questionable circumstances.

But the French investigators work only at the invitation of the Lebanese, and their orders are confidential.

French officials say they have the access they need but will not say whether their inquiry can extend to questioning witnesses or requesting documents. They hand over their findings to the Lebanese, but keep a mirror copy for a French inquiry. The FBI is also joining at Lebanese authorities’ invitation.

Top Lebanese officials, including President Michel Aoun, have rejected calls for an independent probe, describing it as “a waste of time” and suggesting it would be politicized.

In its last decision before resigning under pressure, six days after the explosion, Prime Minister Hassan Diab’s government referred the port explosion case to the Higher Judicial Council, Lebanon’s highest justice authority, to carry out the investigation.

An argument then ensued with the outgoing justice minister over the investigation’s lead judge. The outgoing minister proposed a figure whom the panel rejected as too close to Aoun’s party. After wrangling back and forth, they settled on a compromise, Judge Fadi Sawwan, a former military investigating judge.

The Council itself is made up of 10 people, eight of whom are appointed according to the interests of the various political factions and religious sects in line with Lebanon’s sectarian power-sharing system.

The authorities have so far arrested at least 19 people in connection to the blast, including the head of the Customs Department and his predecessor, as well as the head of the port.

Lebanese say they want to see top officials who knew about the existence of the ammonium nitrate being investigated.

“They will blame the small guys while the ones who are really responsible will get away with their crime, that’s what will happen,” said Jad, a 38-year-old computer engineer who declined to give his full name in line with his company’s regulations not to discuss politics.

“Look, it’s simple. If this time there is no credible, serious investigation that will lead to the punishment of everyone responsible for this disaster, it is goodbye Lebanon. No one will ever want to live in this country again,” he said, standing on a bridge overlooking the decimated port. He had come to inspect the damage.

Lebanese forensics expert Omar Nachabe said the public infighting about the name of the lead investigator is a bad sign that casts doubt on the credibility of any local investigation.

“If I am a Lebanese citizen, my capital (city) has been destroyed. I want a quick and serious investigation, yet the government has not shown until now that it is up to the task,” he told the local channel LBCI. He lamented the time wasted before the explosion was referred to the HJC and the bickering that continues till now.

Explosions have marked a grim timeline in Lebanon’s modern history and have killed presidents, prime ministers and countless journalists and activists during the country’s 1975-90 civil war and beyond.

Almost none of the perpetrators were ever arrested or tried, and the truth was invariably buried. Lebanese had high hopes that the UN-backed tribunal investigating the 2005 killing of Prime Minister Rafik Hariri would be a chance to end impunity in Lebanon. But it took 15 years and was marred by doubts, politics and more deaths. The tribunal is to issue verdicts Tuesday.

International involvement in the investigation might bring some truth, but bringing justice is more complicated. Dov Jacobs, an international legal scholar based in the Netherlands, said the shooting down of Malaysia Airlines Flight 17 over eastern Ukraine six years ago might be the closest analogy.

In that case, international experts had full access to the site, and international prosecutors charged three Russians and a Ukrainian with involvement in bringing down the plane and the murder of all on board. The men are on trial in a Dutch court in absentia, since none have been extradited.

But in Lebanon, Jacobs said, “the investigation itself is a tool of political influence. It’s one of those frustrating moments where immediate calls for justice are faced with a wall which is the political reality on the ground.”

“We sympathize with and stand by the dear Lebanese citizens on the heart-rending incident of an explosion in the port of Beirut which killed and injured a large number of people and caused severe damage, patience in the face of this tragedy will be registered as another golden chapter of Lebanon’s glories,” said the Leader in a message on his Twitter account.

At least 135 were dead and around 5,000 another was injured by deadly explosions which rocked the Lebanese capital on August 4, The Guardian reported.

The fatal incident which was described by the governor of Beirut Marwan Abboud as “an apocalyptic situation,” occurred when a warehouse at the Beirut port caught fire, triggering a huge explosion.

Several smaller explosions were heard before the bigger one occurred, Lebanon’s official National News Agency (NNA) reported.

According to Abbas Ibrahim, head of Lebanon’s General Security, “highly explosive materials” ammonium nitrate confiscated earlier had been stored at the site.

Footage shared on social media captured the moment of the bigger explosion, with columns of thick smoke billowing fast across several hundreds of meters and shrouding the area.

The governor of Beirut estimated the disaster might have made 300,000 people temporarily homeless and would cost the country in excess of $3 billion.

The scale of the destruction was such that the Lebanese capital resembled the scene of an earthquake, with thousands of people left homeless and thousands more cramming into overwhelmed hospitals for treatment.