Top diplomats criss-crossed Beirut on Friday to supervise growing aid efforts and weigh in on Lebanon's political future, following a deadly port explosion blamed on state corruption.

Foreign Minister Mohammad Javad Zarif of Iran, which backs Lebanon's Hezbollah, met officials in the capital ahead of a speech by the powerful Shiite movement's chief Hassan Nasrallah calling for the formation of a national unity government.

Zarif's visit coincided with those of the top career diplomat of Iran's arch-foe the United States, David Hale, and French Defence Minister Florence Parly.

Iran's Foreign Minister Mohammad Javad Zarif is the latest foreign official to beat a path to Beirut as the calls for reform grow shriller
Iran's Foreign Minister Mohammad Javad Zarif is the latest foreign official to beat a path to Beirut as the calls for reform grow shriller AFP / ANWAR AMRO

Both Hale and Parly have joined calls from the international community for a reform-oriented government that would coordinate aid flooding into the crisis-hit country after the resignation of Prime Minister Hassan Diab's cabinet on Monday.

"For the longer run, we cannot accept more empty promises and more dysfunctional governance," said Hale after meeting the head of the Maronite Church, Patriarch Beshara Rai.

"America is ready to support a Lebanese government that reflects and responds to the will of the people and genuinely commits to and acts for real change."

Zarif said it was for the Lebanese to decide what government they wanted.

Food and construction materials are unloaded from the French helicopter carrier Tonnerre after it docked in what is left of the port of Beirut
Food and construction materials are unloaded from the French helicopter carrier Tonnerre after it docked in what is left of the port of Beirut AFP / JOSEPH EID

"Others should not condition their aid on any change in Lebanon during this emergency situation," he said.

The Iranian foreign minister echoed Lebanese officials in rejecting an international probe into the blast, saying "Lebanon, as an independent country, must be in charge of the investigation".

Protesters filled the streets and clashed with security forces in the days after the August 4 explosion, blaming their political leaders for the negligence they say led to the disaster that killed 171 people and wounded at least 6,500.

Lebanese are shocked and angry at the scale of the devastation wrought across the capital from last week's explosion in the port of Beirut
Lebanese are shocked and angry at the scale of the devastation wrought across the capital from last week's explosion in the port of Beirut AFP / ANWAR AMRO

The tragedy came as a huge stock of hazardous materials stored for several years in a warehouse in the heart of Beirut exploded, despite repeated warnings of the dangers it posed.

The mega-blast revived a street protest movement that had first erupted in October last year against government corruption and a lingering economic crisis.

The top US career diplomat David Hale talks with young volunteers in a hard-hit neighbourhood of Beirut, bypassing the politicians many Lebanese blame for the disaster
The top US career diplomat David Hale talks with young volunteers in a hard-hit neighbourhood of Beirut, bypassing the politicians many Lebanese blame for the disaster POOL / Hussein Malla

Hale and Parly met President Michel Aoun separately on Friday and held talks with civil society representatives.

Both insisted that the new government should reflect the will of the people and implement reform

A new government must have a "mission" and "for a limited period of time, be in charge of carrying out far-reaching reforms", said Parly who oversaw the distribution of aid from the French helicopter carrier Tonnerre.

Lebanon's Shiite Muslim movement head Hezbollah Hassan Nasrallah
Lebanon's Shiite Muslim movement head Hezbollah Hassan Nasrallah AL-MANAR TV / -

She said she urged Aoun to speed up the process of forming a government.

The UN's Special Coordinator for Lebanon Jan Kubis agreed, saying: "Time is of the essence.

"People are suffering and can't wait for endless deliberations," he added after meeting the patriarch.

Diab's successor must be named by Aoun, the target of increasing vitriol from protesters, after consultations with parliamentary blocs representing Lebanon's longstanding political parties -- the very ones that the protesters want to see gone.

Nasrallah on Friday called for the formation of a national unity government -- a model that has existed in Lebanon for years.

"We are calling from now for attempts to form a national unity government, and if that is not possible, then a government that secures the widest representation possible for politicians and specialists," Nasrallah said.

In his second speech since the blast, Nasrallah dismissed the idea of a "neutral government" as a "waste of time," saying there weren't any neutral candidates in the country that could form such a cabinet.

Lebanese authorities named judge Fadi Sawan, who has a reputation for independence and integrity according to judicial sources, to lead investigations into the explosion.

He will not question current and former ministers on the ammonium nitrate that was stocked at the port, but they will be interrogated by a special judicial body.

Public prosecutor Ghassan Oueidat has filed lawsuits against 25 suspects over the Beirut blast, 19 of whom are already in custody, a judicial source said.

Those detained include Beirut port's general manager, Hassan Koraytem, and Badri Daher, director-general of Lebanese customs.

On Thursday, Hale, US undersecretary for political affairs, said the FBI would join the probe "at the invitation" of Lebanese authorities.

France, which on Friday confirmed two French citizens were among those killed in the blast, has opened its own enquiry.

UN experts have called for a prompt and independent investigation, expressing concern at the "impunity" of Lebanese officials.

Families of the blast victims have also called for an international probe.

On Friday, rescue workers continued to recover the remains of those killed in the blast at the devastated Beirut port.

Relatives of three firefighters from the same family, who had tried to put out a blaze that broke out before the blast, were told the remains of two of them had been identified by DNA analysis.