The train was carrying around 250 passengers and crew members on a cross-country route linking the Pacific and the Gulf of Mexico. Nearly 100 people were injured.

The administration provided no details of what the president said was an attack last week linked to U.S. efforts to disrupt drug trafficking from Latin America.

The blueprint covers a broad range of issues, including territory, security guarantees and postwar reconstruction. But Russia has indicated little willingness to end the war.