Colombia's Constitutional Court shut the door on Friday on President Alvaro Uribe's aspirations for a third straight term, ruling unconstitutional a law that would have let voters decide in a referendum whether he could run again.

Colombia warned its forces were on "maximum alert" and were prepared to defend against any attack, amid rising tensions with neighboring Venezuela.

Colombia has said it will seek UN help after Venezuela's President Hugo Chavez instructed his military to ready "for war."

President Alvaro Uribe's government said on Saturday it is dropping a demand that Colombia's main rebel group release all its police and military hostages at once, possibly opening the way for negotiations.

Colombia suspended gas exports to Venezuela for technical reasons, the country's state-controlled oil company said, amid a diplomatic spat between the two neighbors over military deals.

Thousands of people around the world voiced their opposition to Venezuelan leader Hugo Chavez on Friday with protests held in Colombia, across Europe, and even the heart of the Venezuelan capital.

Colombian President Alvaro Uribe has the swine flu and officials have advised other South American leaders who met with him at a summit of the infection, authorities said.

Venezuelan President Hugo Chavez has warned he will break off diplomatic ties with Bogota over a controversial US deal to use Colombian military bases, which he termed a "declaration of war."

The deal, finalized last week, is expected to give the US access to three Colombian air bases, two navy bases and two army bases.

Venezuelan President Hugo Chavez decided to "freeze" relations with neighboring Colombia and recall his envoy over accusations from Bogota that Caracas has links to Colombia's FARC Marxist guerrillas.

Venezuelan President Hugo Chavez said Tuesday he would review ties with Colombia after Bogota agreed to host "US bases" in the country.

More than 20 people have been killed and four injured when the bus they were travelling in plunged into a ravine in northwestern Colombia.

Leftist rebel guerrillas in Colombia have released a former provincial governor they had held hostage for more than seven years.

Colombian drug boss Diego Montoya, who allegedly handled 70 percent of the cocaine trade in the United States and Europe, was extradited on Friday to Miami to stand trial on drugs and murder charges, officials said.

Former Colombian presidential candidate Ingrid Betancourt arrived in Colombia on Saturday for the first time since she was rescued from guerrillas after a six-year hostage ordeal, authorities said.

At least 10 people were killed when a snow-capped volcano in southern Colombia erupted this week, Interior Minister Fabio Valencia said on Sunday.

President Alvaro Uribe fired 20 army officers, including three generals and four colonels, for neglect that allowed the killing of civilians to inflate rebel casualty counts.

Venezuela's leftist President Hugo Chavez and his Colombian counterpart US ally Alvaro Uribe have said they are starting a new phase in bilateral ties leaving behind months of a diplomatic crisis that put Latin America on the boil.