The U.S. law enforcement agency Federal Bureau of Investigation (FBI) and other international investigators will join the Beirut explosion probe, a U.S. diplomat said on Thursday.

According to reports, Lebanon has allowed the FBI to join the investigation.

U.S. Under Secretary for Political Affairs David Hale said it is one way for Washington to help the country deal with the disaster's effects.

"The FBI will soon join Lebanese and international investigators at the invitation of the Lebanese in order to help answer questions that I know everyone has about the circumstances that led up to this explosion," Hale said in an Aljazeera report.

The Beirut explosion killed more than 170 people and injured thousands. It also caused widespread destruction in the country.

It was still unknown what caused the fire responsible for igniting around 3,000 tons of ammonium nitrates stored for years in Beirut's port. However, records showed that the country's top leaders and security officials were aware of the stockpile.

Lebanese officials agreed on Thursday to name the judicial investigator to lead the probe under the Supreme Judicial Council's auspices that handle crimes violating the country's national security and political and state security crimes.

Hale, who was due to arrive in Lebanon for a two-day visit, is expected to reiterate the American government's promise to assist the Lebanese people in recovering from the destruction and rebuilding their lives. 

Washington has offered $18 million in humanitarian assistance to be given by the U.S. Agency for International Development. The United States has been one of the generous donors to Lebanon's armed forces.

Washington sees Hezbollah as a terrorist group and has expressed concerns about the aid not going to the Hezbollah-backed government. 

Beirut Explosion Destruction

According to the World Bank's initial assessment, around 50,000 residential units were damaged, while 80 percent of infrastructures were affected. Wastewater systems and an electrical substation were also part of the recorded damage.

Beirut Governor Marwan Abboud said the damage is around $10 billion to $15 billion, with about 300,000 people left homeless.

Lebanese officials noted that around 60 historic buildings in Beirut are at risk of collapsing due to the destructive port explosion.

The United Nations Educational, Scientific and Cultural Organization (UNESCO) said some 640 buildings were at risk of collapse. 

State of Emergency

Lebanon's government has imposed a state of emergency on Thursday, giving the military power during public outrage due to alleged official corruption and political uncertainty.

The blast changed the face of the capital and forced the government to resign on Monday. Before its resignation, the government declared a state of emergency that gave the military the power to impose curfews, prevent public gatherings, and censor media.

Rights lawyer Nizar Saghieh said there is incredible chaos. Saghieh noted that they were waiting for the army to help in the country's reconstruction, and they were not expecting the armed forces to be an extension of power.

France's defense minister is set to arrive in Beirut on Thursday. The country has been leading efforts to help Lebanon rise from the destruction.

France has also been talking to political parties to hasten the formation of a new government.

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