The leader of an attempted coup last Sunday in the Democratic Republic of Congo (DRC) has been killed and about 50 people including three American citizens arrested, a spokesperson for the Central African country’s army told reporters.

Gunfire rang out around 4am in the capital Kinshasa as armed men attacked the presidency in the city centre, according to spokesperson Sylvain Ekenge.

The coup attempt was led by self-exiled opposition leader Christian Malanga before he was killed at the presidential palace and his son, a US citizen was arrested with two other Americans.

Clips shared on social media show one of the Americans, a white man with blood around his mouth, sitting on the ground next to standing Congolese soldiers. “I am shocked by the events of this morning and very concerned by reports of American citizens allegedly involved,” US Ambassador to the Congo Lucy Tamlyn said in a social media post.

“Please be assured that we will cooperate with the DRC authorities to the fullest extent as they investigate these criminal acts and hold accountable any US citizen involved in criminal acts.”

The chaos comes months after President Felix Tshisekedi was re-elected to a second term in a disorderly vote that critics claimed lacked transparency.

Tshisekedi has yet to name a government after he appointed a prime minister six weeks ago. He also delayed a vote for the parliament’s leadership that was originally scheduled for Saturday.

The UN’s stabilization mission in the Congo said in a social media post that its chief, Bintou Keita, strongly condemned the failed coup and offered any support Congolese officials need.