Brazil ? Secretary of State Condoleezza Rice said Thursday that all U.N. nations, including Venezuela, have an obligation to go after terrorists and keep them from operating within their borders.

The comment was largely a warning shot for Venezuelan President Hugo Chavez, who U.S. officials suspect has lent support to Colombian rebels. In recent days, Rice and President Bush have sharpened their rhetoric against Chavez while at the same time praising Colombia and other Latin American allies in a bid to isolate the Venezuelan leader and bolster alliances in the region.