Venezuelan President Hugo Chavez threatened to join the rebels in a war to overthrow hard-line Colombian President Alvaro Uribe, a key ally of the United States, deploying tanks, fighter jets and thousands of troops along the Colombian border.

Ecuadorean President Rafael Correa also ordered troops to the border, expelled Colombia's ambassador and recalled its ambassador to Bogota, but left its embassy open. Venezuela closed its embassy in Colombia and ordered all diplomats home.

A weekend battle sparked the mobilization, in which Colombian forces killed a top leader of the Revolutionary Armed Forces of Colombia (FARC), in a camp in Ecuador.

"The obsessive conduct of those who prize the military option sharpens the armed conflict with grave possible consequences" read a statement from Venezuela's Foreign Ministry after the weekend killing of FARC's second in command, Raul Reyes.

On his weekly Sunday talk show "Hello President," Mr. Chavez accused Colombia of "invading" Ecuador, and compared the action to Israeli attacks against Palestinians.

"The Colombian government has become the Israel of Latin America," Mr. Chavez said. He called Colombia a "terrorist" state and its president, Mr. Uribe, a criminal; "Dracula's fangs are covered in blood."

Mr. Correa said Colombia deliberately carried out the strike beyond its borders. "There is no justification," he said last night, snubbing an earlier announcement from Colombia that it would apologize for the incursion.

Colombia's government said yesterday documents found in a jungle camp in Ecuador where Colombia troops killed Mr. Reyes showed ties between the FARC rebels and Mr. Correa, including contacts with his government about political proposals.

Police Cmdr. Gen. Oscar Naranjo said documents found in computers belonging to Mr. Reyes showed contacts between a top Correa government minister and the FARC commander to discuss political proposals and projects on the frontier.

"The questions raised by these documents need concrete answers," Gen. Naranjo said. "What is the state of relations between the Ecuadorean government and a terrorist group like the FARC."

Mr. Uribe has often accused the FARC of using Venezuelan and Ecuadorean territory as safe havens from military attacks.

Mr. Chavez has been trying to negotiate a prisoner exchange between the Colombian government and FARC, which holds hundreds of hostages including three American contractors and former presidential candidate Ingrid Betancourt.

He has brokered the recent release of seven hostages thus far, including four late last month.

During yesterday's television appearance, Mr. Chavez appeared to side with FARC's four decade effort to oust the government and establish a revolutionary state.

"Someday Colombia will be freed from the hand of the [U.S.] empire," Mr. Chavez said. "We have to liberate Colombia."

In another rhetorical flourish, he gave orders to Venezuela's military as millions watched on TV.

"Mr. Defense Minister, move 10 battalions to the border with Colombia for me, immediately — tank battalions, deploy the air force," Mr. Chavez said. "We don't want war, but we aren't going to permit the U.S. empire, which is the master ... to come divide us."

Estimates of the number of troops in 10 Venezuelan battalions ranged from 3,000 to 6,000.

Yesterday's threat pushes already tense relations between the South American neighbors to their lowest point since Mr. Chavez took power in 1999, vowing to make Venezuela a revolutionary socialist state.

Speaking in Texas, U.S. National Security Council spokesman Gordon Johndroe said officials were monitoring the situation.

"This is an odd reaction by Venezuela to Colombia's efforts against the FARC, a terrorist organization that continues to hold Colombians, Americans and others hostage," Mr. Johndroe said.