CARACAS, Venezuela  In the four days since Colombian forces crossed into Ecuador and killed a guerrilla leader taking refuge there, tensions between Colombia  Washington’s top regional ally  and its leftist neighbors have erupted, highlighting the fact that Colombia and its policies are increasingly viewed here as American proxies.

President Hugo Chávez of Venezuela called Colombia the “Israel of Latin America” saying both countries bombed and invaded neighbors by invoking “a supposed right to defense” that he said was ordered by the United States. He has sent troops to the border and expelled Colombia’s ambassador. His agriculture minister said Tuesday that the frontier with Colombia would be closed to stop commerce.

In turn, Colombia said it would file charges against Mr. Chávez with the International Criminal Court, accusing him of assisting Colombia’s largest rebel group.

Meanwhile, President Bush fiercely defended Colombia, which receives $600 million a year in American aid to fight the leftist rebels and drug trafficking. He used the diplomatic crisis to push Congress to approve a Colombia trade deal that has languished for more than a year because of concerns among senior Democrats over human rights abuses there.