The move escalates tensions in a dispute over a Colombian weekend raid inside another of its neighbors, Ecuador, to kill rebels in an operation that Venezuelan President Hugo Chavez says could spark a war in the Andean region.
While Ecuador and Venezuela had poured soldiers toward their borders with Colombia in recent days, there had previously been no sign of a noticeable movement of heavy firepower.
Responding to a Chavez order delivered on Sunday, Venezuela's military said it had started sending 10 tank battalions toward the border and activated its air force and navy. Military analysts estimate such a mobilization could include more than 200 tanks.
Colombia has said it will not deploy extra forces to its borders in response to the neighbors' mobilizations.
The crisis pits leftists allies Venezuela and Ecuador against Colombia, which receives billions of dollars in U.S. military aid to fight drug traffickers and guerrillas.
Ecuador and Venezuela have also cut diplomatic ties in a crisis that has prompted calls from governments around the world for the three Andean nations to avoid any escalation.
Despite Venezuela's move on Wednesday, Ecuador sounded a conciliatory note, offering Colombia a diplomatic way out of the crisis if it apologizes and pledges not to make other raids.
"I hope in the short term relations can be restored," Vice President Lenin Moreno told Colombian radio Caracol.
Led by diplomatic heavyweight Brazil, most Latin American governments have condemned Colombia for entering Ecuador to kill FARC guerrillas and urged it to apologize.
Güncelleme Tarihi: 05 Mart 2008, 18:00