CARACAS, Venezuela — Tensions between neighbors Venezuela and Colombia could spin out of control following President Hugo Chavez's allegation that Colombia and the United States are plotting a military "provocation" against him, analysts say.

Chavez gave no details on his allegation, saying only that it was based on intelligence reports from his government and other nations he did not identify. The president, who has close relations with Cuba, also cited recent visits of three top U.S. officials to Colombia, among them Secretary of State Condoleezza Rice and the head of the Miami-based U.S. Southern Command, Adm. James Stavridis.

The mercurial Chavez has made a habit of denouncing alleged plots to kill or topple him throughout his eight years in power — most often by Washington but sometimes by Colombian right-wing paramilitary units — but seldom provides any evidence to back up his claims.

In 2005 he repeatedly alleged the U.S. military was planning to invade Venezuela under "Plan Balboa." It turned out Plan Balboa was a war game, organized in 2001 by Spain's military — not the U.S. military — whose background documents and Venezuela-like maps were available on the Internet.

A spokesperson for Colombian President Alvaro Uribe, a close Washington ally, declined comment on the Chavez complaint.

But Chavez's latest accusation Friday night raised concerns in both Venezuela and Colombia that the president, while likely only trying to raise bilateral tensions in order to divert attention away from his growing problems at home, may be creating a climate conducive to war.

"This is nearly reaching unmanageable levels," said former Colombian Defense Minister Rafael Pardo Rueda. "This contains the great danger that along such an extensive border (1,300 miles) any unintentional incident can generate a very complicated standoff."

The former chief of staff of the Colombian armed forces, retired Gen. Harold Bedoya, went further: "Everything indicates that there will be aggression from Venezuela" and that "Cuba is surely involved."

"Chavez does everything possible to confirm the signals that indicate he is willing to employ military resources, as long as this furthers the expansion of the Bolivarian Revolution," said Rafael Guarin, a national security expert from the University of Los Andes in Bogota.

In Venezuela, former Armed Forces Inspector General Rafael Huizi Clavier noted that the "very alarming increase in tensions" came after several political defeats for Chavez, including his stunning loss in a Dec. 2 vote on broad constitutional reforms that would have given him vast new powers and allowed him to seek unlimited re-election.

A survey by the Datos polling company unveiled last week showed confidence in the president had fallen 9 percentage points, to 30 percent, since December 2006. Luis Vicente Leon, director of Datanalisis, said his most recent poll showed a "significant" drop in support for Chavez since Dec. 2 but gave no details.

The president's accusations coincide with the launch early this week of "Operation Caribe 01," a series of Venezuelan military exercises scheduled to run until Feb. 3. Some 3,000 troops concluded the first phase of the exercise Friday, which included the mobilization of fighter planes, tanks and helicopters, according to the Bolivarian News Agency in Caracas.

Chavez's accusations against Colombia, which he repeated Saturday, represent a fresh escalation of the war of words that began Nov. 21 when Uribe withdrew his approval for the Venezuelan president's efforts to mediate with Colombia's leftist FARC guerrillas. On Nov. 25 the Venezuelan ambassador to Bogota was recalled for consultations and has not returned, but Uribe did not withdraw his own envoy.

The FARC's Jan. 10 release of hostages Clara Rojas and Consuelo Gonzalez brought a brief thaw, but relations returned to the freezer the next day after Chavez called for the FARC and a smaller Colombian guerrilla group to be recognized as "insurgent armies." Uribe rejected the proposal out of hand, but declined to answer the Venezuelan's continuing insults.

Some 1,200 Venezuelan troops stationed near the border were redeployed to more forward positions last week, ostensibly to halt the smuggling of foodstuffs from Venezuela, where prices are cheaper, to Colombia.

But the Venezuelan armed forces' willingness to engage Colombia is uncertain, analysts said. On the night of Dec. 2, the armed forces were widely reported to have leaned on a reluctant Chavez to accept his defeat.

In an interview with Colombian journalists before Chavez made his allegation, former Venezuelan Defense Minister Raul Isaias Baduel dismissed his recent string of verbal attacks on Uribe. "What he is trying to do is to invent, to gather support around himself under the threat of a supposed external enemy and appeal to a desperate nationalism . . . at a time when people are suffering domestic problems."

"There is a high risk that the Venezuelan armed forces will not heed an order to initiate conflicts with Colombia," said Orlando Ochoa Terin, a Venezuelan defense and security analyst based in New York.