President Hugo Chavez is hailing the forthcoming arrival of 300 Russian-made tanks and armored vehicles, and urging civilians to join government-organized militias to be ready to defend Venezuela from a foreign invasion.

Chavez called on his supporters to undergo military training and join the militias during a Saturday speech that ended around midnight, saying he thinks "it's the obligation" of every member of his socialist party to participate in an ongoing effort to "organize combat groups."

Chavez, a former paratroop commander, said more than 300 armored vehicles and Russian war tanks, including T-72 battle tanks, will be arriving in Venezuela along with radar and air defense systems.

Venezuela has already bought more than $4 billion worth of Russian arms since 2005, including 24 Sukhoi fighter jets, dozens of attack helicopters and 100,000 Kalashnikov assault rifles. And in September, Russia opened a $2.2 billion line of credit for Venezuela to purchase more weapons.

The military acquisitions, coupled with weapons purchases among South American nations including Brazil and Ecuador, have raised concerns of an arms race in the region.

Venezuela must prepare for a possible armed conflict, Chavez said, because the United States and Colombia could attack. He claims U.S. "imperialists" want to undermine his "Bolivarian Revolution," a political movement named after 19th-century independence hero Simon Bolivar.

He vehemently denied that Venezuela plans to attack its neighbor.

Venezuela and Colombia have been feuding for months over the agreement between Bogota and Washington allowing the U.S. military to increase its presence at seven Colombian bases under a 10-year lease agreement.

Colombian and U.S. officials say the deal is necessary to more effectively help Colombia fight drug traffickers and leftist rebels, but Chavez claims the agreement poses a threat to Venezuela.

"We are the No. 1 target on the imperial map of this continent," he said.