MANAGUA, Nicaragua--President Anastasio Somoza's government, claiming near victory against rebels in the north, said yesterday that Venezuela had thrown its military support behind the insurgents, sending warplanes to back a rebel attack in the south.

Venezuela

The Information Ministry statement said Venezuelan planes based in Costa Rica had provided support for a rebel attack on Penas Blancas, a key post on the Costa Rican border. The attack occurred at 4 a.m.

Costa Rica denied the Nicaraguan claim, while Venezuela has not yet issued a statement.

Somoza's national guard, headquartered in Manila, said its forces had completely retaken the northern city of Leon, the nation's second largest city.

The guard also said government troops were fighting rebels in Chinandega and Esteli. The rebels, led by guerrillas of the leftist Sandinista National Liberation Front, launched a general uprising last weekend in an effort to oust Somoza.

Associated Press correspondent Lew Wheaton reported from Leon that entire blocks of the city of 100,000 people lay in ruins after the battle.

"Somoza must go," a stunned woman said. "Only a madman would do something like this. We are not Communists here. Just common people," she added.