The head of the Organization of American States called for Honduras to be excluded from the regional group, nearly a week after President Manuel Zelaya was ousted by the military.
In the Central American nation, fears rose of a violent showdown as crowds gathered in the capital Tegucigalpa ahead of Zelaya's expected return on Sunday.
The interim leaders who ousted Zelaya almost a week ago have said they will arrest him on his return.
"No other alternative exists" but to exclude Honduras, OAS Secretary General Jose Miguel Insulza said in Washington the day after a visit to what he said was an increasingly polarized and tense country.
Zelaya said on Venezuelan television that he would return Sunday accompanied by a handful of Latin American leaders.
He later said he was "optimistic" about the situation following last week's coup, speaking at the OAS meeting in Washington.
Anticipating an OAS suspension, the interim Honduras leaders said Friday that they were pulling out of the body -- a move that was rejected as meaningless by Insulza.
"It's a government which for the 34 member countries and for the international community does not legally exist," Insulza told Chilean radio on Saturday.
In its only ever suspension, the body excluded Cuba in 1962.
"I am planning my return to Honduras... we will arrive at the international airport in Tegucigalpa, Honduras with several presidents, (and) members of international organizations," Zelaya told Caracas-based station Telesur Saturday.
"This Sunday we will be in Tegucigalpa," he said.
Shortly beforehand, Catholic leaders warned of a potential bloodbath if Zelaya returned to the country.
"To this day no Honduran has died. Please think, because afterwards it will be too late," Cardinal Oscar Rodriguez -- the capital's archbishop -- pleaded on national radio and television, reading a message from the country's Bishop's Conference.
Thousands of Zelaya's supporters and opponents have demonstrated daily since the president was bundled away to Costa Rica last Sunday, and brief clashes have broken out between the army and protesters.
It was unclear exactly how many people had been injured and detained, amid growing protests from international rights groups.
Thousands of pro-Zelaya supporters took to the streets of Tegucigalpa once again on Saturday, including some who said they had traveled five days to reach the capital.
Hundreds gathered briefly around the international airport in anticipation of Zelaya's arrival, vowing to return.
"We love Mel," demonstrators shouted, referring to Zelaya's nickname.
A pessimistic Insulza said here late Friday that those who ousted Zelaya last weekend did not plan to reverse the situation, and denounced a "military coup."
Insulza met politicians and legal and religious figures, but not the interim president, Roberto Micheletti, whom he does not recognize.
Micheletti's supporters says the army was justified in ousting Zelaya -- on orders of Congress and the Supreme Court -- because he had called a referendum to change the constitution that they claim he planned to use to extend his rule.
The interim government has said it may consider holding early elections to end the impasse, but now looked set to try to hunker down until scheduled elections in November.
A freezing of millions of dollars of international aid, regional trade blockades and recalls of foreign ambassadors have hit the country in the past week.
With lives also disrupted by night-time curfews -- which suspend some freedoms guaranteed by the constitution -- as well as media blackouts and detentions, tension has risen in one of Latin America's poorest countries.
Zelaya has traveled the region seeking support and said he no longer wishes to change the constitution.
Chavez, Zelaya's main backer, announced that Venezuela would suspend key shipments of oil to Honduras, which he said would drive up gasoline prices.