Colombia's government and the country's largest rebel group announced a truce to end a 50-year guerrilla war, one of the world's longest-ever armed conflicts, the Associated Press reported late Wednesday.

The federal government's deal with FARC must be approved by voters in a plebiscite before the accord is made official. Colombia would be required to implement aggressive land reforms, reform its anti-narcotics strategy and expand the state into rural parts of the country.

President Obama congratulated Colombian President Juan Manuel Santos over the phone Wednesday.

"The President recognized this historic day as a critical juncture in what will be a long process to fully implement a just and lasting peace agreement that can advance security and prosperity for the Colombian people," the White House said in a statement "The President noted that the U.S. was proud that it could stand with Colombia in supporting the pursuit of peace."

Both groups have been in talks for four years. More than 220,000 people have died during the ongoing violence and 5 million others have been forced out of their homes.

Obama pledged to continue U.S. support of the Colombian people through the Peace Colombia framework that was announced in February.