Prime Minister Vladimir Putin said Tuesday that Russia will respond calmly to an increase in NATO ships in the Black Sea in the aftermath of the short war with Georgia, but promised that “there will be an answer.”

A humanitarian aid flight carrying 17 people crashed on a ridge in eastern Congo, and the U.S.-based group that operated the route said Tuesday there appeared to be no survivors.

The 21-seat Beechcraft 1900 aircraft disappeared in bad weather late Monday with two crew members and 15 passengers on board, said Elisabeth Byrs, a spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs.

The plane was located Tuesday morning, about nine miles northwest of the airstrip at Bukavu in eastern Congo, its intended destination, Byrs told journalists in Geneva.

Air Serv International, which runs the twice-weekly aid delivery between Kisangani and Bukavu, said in a statement that the plane was located on a steep ridge and that helicopter surveys suggested all 17 aboard had died.