Diplomats and government officials say at least 150 people, including Chinese workers, have been killed in a series of blasts in the Republic of Congo capital, Brazzaville.

Authorities say a series of powerful explosions at a weapons depot along the Congo River rocked the city early Sunday.

A Chinese consulate official in Brazzaville told Beijing's Xinhua news agency that at least four Chinese workers were among those killed and that dozens of others were injured. Duan Jinzhu is quoted saying the embassy was trying to obtain more information about the casualties.

The state news agency reported the workers belonged to the Beijing Construction Engineering Group in the Republic of Congo.

It was not immediately clear what caused the explosions.

The series of powerful blasts also shook Kinshasa, the capital of the Democratic Republic of Congo across the Congo River.

Witnesses said the blasts sent large plumes of smoke into the air and could be seen from Kinshasa.