Most countries do not seem to be following Mr Morales' (R) lead
Bolivian President Evo Morales has accused his Colombian counterpart of betraying Latin Americans with a plan to let US troops use Colombian bases.
Mr Morales said that Bogota's plan was aimed at countering the efforts of left-wing governments like his.
He said those governments were fighting for greater social justice.
However, Brazil and Chile have said they will respect Colombian President Alvaro Uribe's sovereign right to carry out the plan.
Their acceptance came after Mr Uribe completed a three-day tour of the region in a bid to calm fears over his decision to open seven military bases to US forces.
Correspondents say this tacit acceptance sends a sign that most countries in the region are not prepared to follow the harder line taken against Colombia by countries like Bolivia and Venezuela.
Venezuelan President Hugo Chavez - who cut ties with Colombia last month - has said he fears the move amounts to preparation for an invasion of his country by US forces.
Washington strongly rejects any claims that it is planning an invasion of Venezuela.
The US has been forced to look for a new base after Ecuador refused to renew the lease on its Manta base, which the US military was using for anti-narcotics operations.