Top commanders of the leftist rebels fighting the U.S.-backed government of El Salvador are frequently in Managua, Nicaragua, where they are in constant touch with Sandinista officials about questions of arms supply, strategy and tactics, according to a defector from the Nicaraguan counterintelligence agency.

Miguel Bolanos Hunter, echoing charges long made by the Reagan administration, said Nicaragua has been providing guns, advice, coordination and training to the guerrillas in El Salvador since they began trying to overthrow the government there in 1979.

However, "a river" of arms shipments from Cuba and the Soviet Union through Nicaragua to El Salvador has all but stopped, Bolanos said, because "they now have five times more than what we had against ousted dictator Gen. Anastasio Somoza."

Bolanos claimed that Nicaragua has become "a new Cuba" in training guerrilla forces from throughout Latin America. As a Sandinista official charged with working against the U.S. Embassy, Bolanos said, he met visiting guerrilla leaders from Colombia, Argentina, Chile, Guatemala, Costa Rica and El Salvador, all of which have centers of operation in Managua.

The Salvadorans have two houses in Managua's residential Las Colinas district, one a communications center and the other a "safe house" for visiting Salvadoran guerrillas and for meetings with Nicaraguan officials, Bolanos said.

Visiting Salvadorans also use houses belonging to Nicaraguan officials, and some of the guerrilla chiefs are in Managua more than they are in El Salvador, he continued. "They fly over to the mountains for a day to boost the morale of the troops and fly out again at night sometimes," he said.

Nicaragua is better than Cuba as a training base for guerrillas because it has regular commercial air transport and permeable borders, while Cuba's island status makes it hard for guerrillas to come and go without being spotted, he said.

Bolanos said he had fought during the 1979 Sandinista takeover of Managua with a Salvadoran known as "Memo," who then returned to El Salvador and became second in command of the guerrilla units fighting in Morazan province in northeastern El Salvador. Bolanos said he encountered Memo in Managua last October, "and he said they were using the same methods to get arms as we used in Nicaragua."

These methods, Bolanos continued, included twice-daily airplane flights to barricaded sections of highway in guerrilla-controlled areas. Each plane carried 30 to 40 guns, he said, and medicine and ammunition often were dropped by parachute, while other arms came concealed in trucks or overland on mules.

His cousin, Miguel Guzman Bolanos, is in charge of arms distribution in Nicaragua, Bolanos said, and told him that Luis Carrion, a member of the Sandinista directorate, had been promised in a 1980 trip to the Soviet Union that the Soviets would provide the Nicaraguans two AK47 machine guns for every weapon they gave the Salvadoran guerrillas. Those included U.S.-made guns the Sandinistas obtained from Cuba, which in turn got the guns from Vietnam, Bolanos said.

Managing the arms flow to El Salvador could be annoying, Bolanos continued. A friend of his, Richard Lugo, a navy chief, was upset one evening at being called and told to go to an Atlantic coast port at midnight to meet a Cuban boat loaded with guns for El Salvador.

"He had an arrangement with a woman friend that night and he didn't want to go," Bolanos said. "He said it was too bad that somebody always had to be standing behind these Salvadorans and taking care of them."

Bolanos described the aftermath of the murder in Managua last April 6 of Salvadoran guerrilla leader Melida Anaya Montes, which he said occurred across from the house from which Bolanos' agents were watching the nearby residence of a U.S. Embassy political officer. Bolanos' superior, Lenin Cerna, director of the Interior Ministry's department of state security, accused the Sandinista party's foreign affairs head, Julio Lopez, of having failed to guarantee the guerrilla leader's security and of failing to let Cerna know about the arrangements.

Montes was betrayed to her killers by her cook and one of her security guards, Bolanos said, and was killed for "political reasons--she was just back from Cuba and wanted to have more dialogue between the guerrillas and the Salvadoran government."