Here is what we know so far:

A German diplomat was killed in Tuesday's twin blasts at the Lebanese capital of Beirut, the German foreign ministry said on Thursday.

Beirut blast death toll has climbed to 135, with around 5,000 people wounded and dozens of others missing. The number of casualties is expected to rise.

The cause of the blasts remained unknown on Wednesday, but reports point to 2,750 tonnes of ammonium nitrate stored in a warehouse in Beirut's port for six years as a possible cause of the explosions.

Lebanon's Cabinet on Wednesday declared a two-week state of emergency in Beirut.

World leaders offered support and condolences to the country, including Gulf nations in the region. Israel has also offered humanitarian aid.

The medical unit of the Chinese peacekeeping forces to Lebanon said it will provide medical aid to Beirut.

The Chinese government launched an emergency response mechanism on Wednesday to offer humanitarian assistance to Lebanon.

President Xi Jinping sent a message of condolence to Lebanese President Michel Aoun on Wednesday over explosions in the country's capital, Beirut, that killed more than 110 people.

In the message, Xi said he was shocked to learn about the explosions, which caused heavy casualties and property losses.

"On behalf of the Chinese government and people, and in my own name, I would like to express my sorrow for the loss of life and extend my deep condolences to the families of the victims as well as the injured," Xi said.

Two explosions rocked Beirut on Tuesday, leaving more than 110 people dead and 4,000 injured, according to multiple media reports.

The blasts hit the Port of Beirut at around 6:10 pm local time, shaking buildings all over the city. The number of casualties is expected to rise as search and rescue efforts and medical treatment of the injured continue.

The cause of the blasts remained unknown on Wednesday, but reports point to ammonium nitrate stored in a warehouse in Beirut's port for six years as a possible cause of the explosions.

Lebanon's Cabinet on Wednesday declared a two-week state of emergency in Beirut, and handed control of security there to the military, Reuters reported.

The Lebanese government also said it was putting an unspecified number of Beirut port officials under house arrest pending an investigation, according to AFP.

Following the explosions, Aoun had called for an emergency meeting of the country's Supreme Defense Council, according to the presidency's Twitter account.

Lebanese Prime Minister Hassan Diab declared a national day of mourning on Wednesday for the victims of the explosions.

The Chinese embassy in Lebanon told reporters that one Chinese person was slightly injured and no Chinese had been killed in the explosion so far.

Chinese Foreign Ministry spokesman Wang Wenbin said in Wednesday's news briefing that China expresses deep sympathy and condolences over the incident and is willing to provide assistance within its capacity for Lebanon in handling the incident.