The US secretary of state will meet with the nominally Marxist rebel group on Monday while visiting Cuba, using the meeting to check in on progress to end Colombia's half century of conflict.

A source at Colombia's Office of the High Commissioner for Peace and another source close to the government confirmed the Kerry meeting.

"It has been scheduled, the meeting with Kerry," FARC negotiator Pastor Alape told the Reuters news agency, adding that the rebels would first meet the US special envoy for Colombian peace talks, Bernard Aronson, to agree on an agenda.

The conflict between the Colombian government and the FARC has killed some 220,000 people and displaced millions since 1964

More than half century of bloodshed

The US-allied government and Marxist militants are attempting to reach a deal that would be placed before Colombian voters for approval, with a United Nations mission supervising rebel disarmament.

Colombian President Juan Manuel Santos and FARC leader Rodrigo "Timochenko" Londono had set a self-imposed March 23 deadline to reach a comprehensive peace pact but have since conceded that goal may not be realistic.

Washington designated the FARC as a foreign terrorist organization in 1997, and many of its leaders have been indicted in the United States on charges of narcotics trafficking.

Baseball diplomacy

The unprecedented meeting will coincide with an exhibition game between Major League Baseball's Tampa Bay Rays and Cuba's national team on Tuesday.

The game will be attended by President Barack Obama, who on Sunday became the first sitting US president to visit Cuba in nearly 90 years.

Negotiators from the FARC and Colombia's government have also been invited to attend the game with the US president and Cuban leader Raul Castro.

jar/cmk (AP, Reuters)