Colombian President Juan Manuel Santos opened a new national dialogue Monday to seek peace with FARC rebels after voters narrowly rejected a deal to end the country's half-century conflict.

In a televised address, Santos said he had asked former vice president Humberto de la Calle -- the government's chief negotiator who earlier offered his resignation -- to "begin discussions as soon as possible addressing all the necessary issues to have an agreement and realize the dream of every Colombian to end the war with the FARC."