The United States fully supports Colombia's efforts to reach a deal to end Latin America's longest civil war, Vice President Joe Biden said Wednesday.

Colombian President Juan Manuel Santos was re-elected Sunday in a runoff seen as a referendum on his bid to end the 50-year-old conflict.

"As I told you here in Bogota last spring, just as the United States has supported Colombian leaders on the battlefield over the years, we fully support you at the negotiating table," Biden said at a news conference alongside Santos.

The Colombian government is trying to reach peace with the Revolutionary Armed Forces of Colombia (FARC) and smaller National Liberation Army (ELN), which have 8,000 and 2,500 fighters respectively.

"Nothing would make me happier, Mr president, than to come back to Colombia for the signing of the peace accord," stressed Biden, on a regional tour that has already taken him to Brazil.

He also has stops planned in the Dominican Republic and Guatemala.

"I know there is a lot left to do, but I have absolute confidence in your determination. And I'm confident that whatever the result may be, it will be for the benefit of the Colombian people," Biden said.

Santos stressed the importance of US support to the peace process, especially looking ahead toward setting policies for the post-war era.

Colombia is the closest ally of the United States in Latin America. Bogota has received $8 billion since 2000 as part of Plan Colombia, opposing the insurgencies and drug traffickers.