**The Venezuelan President, Hugo Chavez, has accused Colombia of carrying out a military incursion into Venezuela.**Mr Chavez said Colombian soldiers had recently been seen crossing the Orinoco river, which forms part of the border, and entering Venezuelan territory.
He said the alleged incursion was a “provocation” by Colombia’s government.
The accusations came shortly before a summit of South American leaders is due to discuss a Colombian proposal to allow US troops access to its bases.
Mr Chavez has been embroiled in a diplomatic row with his Colombian counterpart, Alvaro Uribe, ever since news of the plan emerged.
‘Growing threat’
During his weekly TV show on Sunday, President Chavez ordered his troops to get on a war footing along the border with Colombia.
“The Yankees have started to command Colombian military forces”
Venezuelan President Hugo Chavez
Colombia’s rocky regional relations
Uribe tours region over US pact
“The threat against us is growing,” he said. “I call on the people and the armed forces - let’s go, ready for combat!”
He said Colombian soldiers had “crossed the Orinoco River in a boat and entered Venezuelan territory” and that when Venezuelan troops arrived, they had gone.
“This is a provocation by the government of Uribe,” he said. “The Yankees have started to command Colombian military forces.”
Venezuela’s foreign ministry would file a formal complaint, he added, warning that its military would “respond if there’s an attack”.
Mr Chavez said he would use this week’s summit of the Union of South American Nations (Unasur) in Ecuador, to urge his allies in the region to pressure President Uribe to reconsider plans to increase the US military presence.
So far, only Bolivia and Ecuador have condemned the plan, while other countries like Chile and Brazil have said they will respect whatever decision Colombia takes.
Ecuadorian President Rafael Correa, who has already announced he would not be renewing the lease of the current US base in Ecuador, said he was concerned about an increase in military activity across the border his country shares with Colombia.
Mr Correa broke off relations with Colombia in March last year when Colombian troops hunting down members of the left-wing Revolutionary Armed Forces of Colombia (Farc) killed 19 of them in Ecuadorian territory.
“We cannot ignore this threat,” Mr Chavez said.
The Venezuelan leader has said he is concerned that the seven Colombian bases could become a new Guantanamo, or an enclave of US influence, like Israel.
Mr Uribe has said the increased US military presence will help Colombia in the fight against drugs trafficking and left-wing rebel groups. He also says US law would only permit a maximum of 1,400 troops and civilian contractors to be based there.
Correspondents say this is not the first time tensions have risen between the Venezuela and Colombian presidents.
Last year, a war of words culminated in the Venezuelans despatching tanks and heavy armour to the border.