Colombian President Juan Manuel Santos on Friday instructed Cabinet ministers who have held four days of talks aimed at ending a general strike in the agricultural sector to break off negotiations with farm leaders, citing the impossibility of reaching an agreement.

"Our patience has run out," the president said in a nationwide address.

"Unfortunately, despite the effort that was made, despite the concrete proposals and the time devoted, the only response has been to constantly postpone an accord. Because they don't want an agreement, or perhaps because they're not being allowed" to pursue one, the president said.

Santos attributed the protesters' intransigence in the talks to people or groups "who only want to destabilize," directly blaming the leftist Patriotic March movement for the situation.

The president said he had ordered the military to patrol Bogota's streets after Thursday's disturbances left two dead, more than 100 injured and stores and other establishments vandalized in the capital.

Protest marches in Bogota and other cities in support of the farmers were followed by violent incidents.

"These actions anger and upset all Colombians," the head of state said, adding that "unfortunately many of these demonstrations are infiltrated by vandals bent on doing damage."

"I deployed the military in Bogota (Thursday) night and I'll do the same starting Friday in any municipality or any area where our soldiers' presence is needed," Santos said.

Some 50,000 troops also have been instructed to assist police in clearing roads that have been blocked since the strike began on Aug. 19, according to the president.

The farmers, meanwhile, said Friday they would lift their road blockades but continue to stage protests until an agreement is reached with the government.

The farm sector partially blames its troubles on Colombia's free-trade agreement with the United States, which took effect in May 2012 and has allowed cheaper U.S. imports to enter the Andean nation. EFE