Tegucigalpa, Honduras  - Soldiers on Sunday morning staged a coup against Honduran President Manuel Zelaya, evicting him to Costa Rica and confiscating documents from the executive mansion.

Honduras' unicameral National Congress later Sunday agreed to remove Zelaya from office and designated Congress Speaker Roberto Micheletti as his successor.

Soldiers apprehended Zelaya and forced him to depart to Costa Rica after days of mounting political tensions over a proposed referendum, which Zelaya's opponents said was nothing more than a power grab.

A vote had been planned for Sunday that would have registered popular support for a proposed constitutional change that could have led to Zelaya's re-election. Current law would have prevented him from running again after his term ended in November.

The country's supreme court said it had authorized the coup to hinder the referendum. If approved, the non-binding referendum would have given Zelaya authority to progress with plans to rewrite the constitution.

According to the statement, the military was told to cooperate with government prosecutors to confiscate all documents associated with the referendum.

The statement did not make clear who gave the authority for Zelaya's arrest and deportation to Costa Rica. It stated that the military had worked to protect the rule of law and that all its actions were based on judicial orders.

Zelaya decried the coup from Costa Rica, where he said soldiers sent him after the military action.

"There is no justification for this coup," said Zelaya in an interview with a Venezuelan broadcaster that was also carried by CNN.

"It was a kidnapping," said Zelaya. He said the soldiers threatened him with guns. "They pointed at my chest and head and said they were just following orders."

Zelaya later said he still plans to attend a regional leadership summit in Managua on Monday.

Speaking in Costa Rica, he said he continues to serve as the legitimate president of Honduras. He called on the people of Honduras to engage in peaceful resistance to the coup.

"The Honduran people will never accept this illegal regime," he said.

In a White House statement, US President Barack Obama said he backed a call by the Organisation of American States (OAS) urging all the parties in the Central American country to respect the democratic and legal rules of Honduras.

Senior US administration officials told reporters that the United States continues to recognize Zelaya as the democratically elected leader of Honduras. Washington would join the OAS in condemning the coup and working to restore democratic order, the officials said, speaking on condition of anonymity.

The OAS condemned the coup and said it would not recognize any government but that of ousted President Manuel Zelaya. The international body's Permanent Council called for the "immediate, safe and unconditional return" of Zelaya to his office in a resolution adopted at an emergency meeting at its Washington headquarters.

It called the coup "an unconstitutional alteration of the democratic order" and also condemned the reported detention of Foreign Affairs Minister Patricia Rodas and other government officials. The OAS General Assembly will hold a special session on the coup on Tuesday.

Supporters of Zelaya stormed into downtown Tegucigalpa, shouting and occasionally lashing out at soldiers, who did their best to ignore them out of fear of provoking more violence.

Zelaya has been locked in a power struggle with other state institutions over efforts that seem designed to extend his term in office and change parts of the constitution. Sunday's referendum was to gauge public support for those proposals.

Local media reported that military units had occupied the executive mansion and confiscated materials that Zelaya had prepared for use in the vote.

His efforts have met with resistance from various institutions. The supreme court and Congress have both opposed the referendum. He also ran into opposition from the army when General Romeo Vasquez Velasquez refused a presidential request to provide logistical support for the referendum.

That standoff led Zelaya to fire Vasquez Velasquez, a move that was ruled unconstitutional by the supreme court on Thursday.

The Honduran military on Friday had deployed hundreds of soldiers across the capital of Tegucigalpa to maintain calm. Soldiers were told to keep potential troublemakers out of the capital, though those who did not seem to pose a threat were allowed regular access.

Under the current constitution, Zelaya cannot run for re-election in the presidential balloting November 29. Zelaya was elected in 2006 as a conservative, but later reversed his policies and now has scant support from leftist groups and trade unions.

The tension has caused international waves, with leaders of left- leaning Latin American leaders like Venezuela's Hugo Chavez and Nicaragua's Daniel Ortega weighing in to back Zelaya. Chavez has used similar referendums to change the constitution and extend his term in office.

Honduran election officials confirmed that presidential elections will go ahead in November as originally scheduled, despite the coup. (dpa)