Brazil and the U.S. urged Colombia and Venezuela on Tuesday to talk out their differences after Venezuelan leader Hugo Chavez ordered his military to prepare for a possible war with his neighbor.

The push for diplomacy came as many in both Colombia and Venezuela dismissed Chavez's words as an attempt to distract attention from domestic problems, including the struggling economy and water shortages and power blackouts.

Chavez has warned that troops he ordered to the Colombian border should be ready for a possible conflict if the U.S. attempts to provoke a war between the South American countries. He cited a recent deal between Bogota and Washington giving U.S. troops greater access to Colombian military bases as a threat to regional stability.

Brazil's defense minister, Nelson Jobim, played down the risk of an armed conflict.

"We believe that everything can be resolved with dialogue," Jobim said in Brasilia. "I don't think the tension is going to increase; it's part of the rhetoric of the continent."

In Washington, U.S. State Department spokesman P.J. Crowley said: "We are very much aware of recent tensions along the Venezuelan-Colombia border."

"I certainly don't think this is about the United States," Crowley added. "But we certainly would encourage dialogue between Venezuela and Colombia and a peaceful resolution of the situation along their border."

The Organization of American States also called on Colombia and Venezuela to settle their problems through dialogue.

Tensions have escalated and trade has dropped dramatically since the diplomatic crisis erupted in July over the plan to grant U.S. military aircraft and warships expanded access to Colombian bases, including $46 million in construction at the Palanquero air base in Colombia's central Magdalena valley.

Colombia's government has sought to assuage Venezuela's concerns, saying U.S. troops would be operating solely on Colombian soil to help its military combat drug trafficking and leftist rebels. But critics of U.S. policies argue the accord is meant to help Washington expand its influence and interference in the region.

Many in Venezuela oppose the idea of a war with Colombia and view the suggestion of a conflict as pure bluster.

A poll released Tuesday by the Caracas-based polling firm Datanalisis found that nearly 80 percent of Venezuelans said they would disagree with Chavez declaring war on Colombia. The poll consulted 1,300 people and was completed last month, before Chavez's latest remarks. The poll had an error margin of 3 percentage points.

That and other surveys have shown a recent decline in Chavez's popularity as the country copes with its economic woes and other problems.

"It's always more interesting to get the people talking about a war with Colombia than to get them talking about issues like inflation, water problems or electricity problems," pollster Luis Vicente Leon of Datanalisis told The Associated Press.

The biggest effect of the crisis so far has been the fall in trade. The Colombian-Venezuelan chamber of commerce estimates bilateral trade this year could fall 20 percent from 2008, to around $4.5 billion.