Colombia's largest Marxist rebel group has ruled out a prisoner exchange with the government as long as Alvaro Uribe is president.

In a statement on its website, the Revolutionary Armed Forces of Colombia accused President Uribe of lacking the political will to resolve the situation and instead has focused on the military aspect of the war.

The Colombian government has previously offered to meet with FARC rebels to discuss a possible prisoner swap.  The rebel group is holding scores of hostages, including a presidential candidate and three American contractors.

Meanwhile, police in the southern Putumayo region accuse FARC rebels of blowing up oil wells and an electricity tower near the Ecuadorian border over the last few days.

FARC has been at war with the Colombian government for more than four decades, in a conflict that has claimed tens of thousands of lives.