BOGOTA, Colombia (AP) — Colombia's president compared Nicolás Maduro to Serbian war criminal Slobodan Milosevic as he goes on a diplomatic offensive to corral the Venezuelan socialist, warning that he would be making a "stupid" mistake if he were to attack his U.S.-backed neighbor.

Ivan Duque made the comments in an interview Saturday with The Associated Press before traveling to New York where he is expected to condemn Maduro before the United Nations General Assembly as an abusive autocrat who is not only responsible for the country's humanitarian catastrophe but is also now a threat to regional stability for his alleged harboring of Colombian rebels.

"The brutality of Nicolas Maduro is comparable to Slobodan Milosevic, "said Duque. "It must come to an end."

While Duque refused to rule out a military strike against the Marxist rebels he claims are hiding out across the border, he said any aggression by Venezuela's armed forces would immediately trigger a regional response that could include additional sanctions and diplomatic actions.

"If they consider doing something so stupid, they know what the consequences will be," said Duque.

Duque has ratcheted up pressure against Maduro in recent weeks after a small band of dissident leftist rebels decided to break with Colombia's historic peace process and take up arms against the state again, contending that the government has betrayed the accord aimed at ending over five decades of bloodshed.

The Colombian leader is expected to accuse Maduro of breaking a U.N. Security Council resolution passed after the Sept. 11, 2001 terrorist attacks by offering the rebels refuge.

The embattled Venezuelan president has repeatedly denied those accusations. Though Maduro himself will not attend this year's U.N. General Assembly, his delegates say they'll levy similar charges against Duque, accusing him of failing to act against illegal armed groups plotting attacks against his government from Colombia.

"The Colombian oligarchy wants to lay the ground for an armed aggression against Venezuela," Communications Minister Jorge Rodriguez said recently.

The growing tensions along the border have potentially dangerous and wide-reaching geopolitical implications.

At the U.S.' urging, hemispheric allies recently dusted off a mutual defense treaty from the Cold War that requires the 19 signatory nations to come to the rescue of one another in the event of an external threat.

Foreign ministers from most of the 1947 Rio Treaty nations are scheduled to meet Monday to weigh multilateral sanctions. Though the accord permits a joint military response, Colombia and other nations have said that option remains firmly off the table.