Colombia and Venezuela have agreed to increase security along their long and porous border to prevent frequent crossings by armed Colombian groups.
All smiles at the summit but the two men have sharply contrasting politics
The agreement follows several weeks of growing tension as Colombia accused Venezuela of providing a haven for left-wing rebels.
Meeting in eastern Venezuelan, President Hugo Chavez and his Colombian counterpart, Alvaro Uribe, agreed that the civil war in Colombia increasingly threatened the entire Andean region.
"Colombia has long suffered terrorism sponsored by drug-trafficking. It has become a threat to all of our neighbours," Mr Uribe said, after their summit in the town of Puerto Ordaz.
Everything would be done to prevent guerrillas and paramilitaries from penetrating the 2,200 kilometres (1,500 mile) border, he said.
"Call them archangels or terrorists. The important thing is to capture them," he said, a reference to Mr Chavez's refusal to call the left-wing rebels terrorists.
President Chavez said he and Mr Uribe had decided to deal with the sensitive border issue in private in the future and avoid what he called "microphone diplomacy".
Both men also played down tensions fuelled by reports that Venezuelan aircraft bombed right-wing paramilitaries inside Colombia in March.
Mr Chavez has repeatedly denied providing a refuge for Colombian guerrillas, blaming such allegations on groups determined to undermine bilateral relations.
His opponents alleged everyone had passed through the Venezuelan capital, Mr Chavez said, "including Osama Bin Laden and Saddam Hussein. I'm not going to respond to that."
The two men also announced a series of co-operation projects, including a deal for Venezuelan importers to pay around $350 million owed to Colombian exporters.
Payment had been blocked by tight currency controls introduced by Venezuela to shore up its own currency - a move which hit bilateral trade hard.
Before the talks, Mr Uribe gave Mr Chavez a poncho, saying it was not something Manuel Marulanda, the leader of the Revolutionary Armed Forces of Colombia, would wear.
Mr Chavez insisted he took the remark as a "good joke".