Protests erupt, gunshots heard after Honduras coup

He said that if the Venezuelan ambassador was killed, or troops entered the Venezuelan embassy, "that military junta would be entering a de facto state of war, we would have to act militarily." He said, "I have put the armed forces of Venezuela on alert."

Chavez has in the past threatened military action in the region but never followed through.

The United States and other foreign governments condemned the coup. Obama called for calm.

"Any existing tensions and disputes must be resolved peacefully through dialogue free from any outside interference," he said in a statement.

A senior Obama administration official said later that Washington recognizes only Zelaya as president.

The coup could be an early test for Obama as he tries to mend the United States' battered image in Latin America, a regional expert said.

"This is a golden opportunity to make a clear break with the past and show that he is unequivocally siding with democracy, even if they (Washington) don't necessarily like the guy," former Costa Rican Vice President Kevin Casas-Zamora told Reuters in Washington.

Honduras was a staunch U.S. ally in the 1980s when Washington helped Central American governments fight left-wing guerrillas.

Chavez, who is known for his stridently anti-U.S. rhetoric and has in the past accused the United States of backing his own removal, said there should be an investigation to see if Washington had a hand in Zelaya's ouster. The White House denied any participation in the coup.

The United States still has about 550-600 troops stationed at Soto Cano Air Base, a Honduran military installation that is also the headquarters for a regional U.S. joint task force that conducts humanitarian, drug and disaster relief operations.