Nicaraguan Interior Minister Tomas Borge said today that his government is "ready to talk and to negotiate peace in Central America" despite what he said were "reservations" and a "historical mistrust" of the United States.

Borge's remarks to foreign journalists came as the government announced that 11 "counterrevolutionaries" and three Sandinista soldiers had been killed yesterday in a shootout along the Honduran border. The government also charged that patrol boats from El Salvador and Honduras had fired on Nicaraguan boats in the Gulf of Fonseca, on which all three countries border, in two separate incidents Monday and yesterday.

The sea confrontations--in which Nicaragua said that two employes of the national fishing industry were missing and presumed dead, and that one Sandinista soldier was wounded--were the subject of terse protests by the Nicaraguan Foreign Ministry last night.

Nicaraguan Defense Minister Humberto Ortega warned tonight of a possible invasion of the country, Reuter reported. Ortega said in a press conference, without giving details, that "in recent hours high military officers from some South American countries have arrived in Central America to collaborate with the aggressive plans of North American imperialism."

Honduran Foreign Minister Edgardo Paz Barnica reportedly replied today that his country is seriously worried about armed encounters that he said were provoked by Nicaragua. El Salvador has not commented.

Borge, a longtime Marxist and one of the most powerful figures in the Sandinista leadership, said Nicaragua is seriously studying all proposals for a negotiated resolution to the explosive tensions developing in the region but suggested that the negotiations should begin immediately. "Afterwards it is going to be very difficult," he said in an apparent reference to Salvadoran guerrilla pledges to launch a major offensive in El Salvador before elections scheduled for March 28.

Borge's tone was different from yesterday, when he told reporters who questioned him at the airport: "It is impossible to negotiate with a pistol pointing at one's chest. The first thing the United States must do is take back its threats of aggression against us."

In New York, Jeane Kirkpatrick, U.S. ambassador to the United Nations, confirmed that she met there earlier this week with Julio Lopez, the principal foreign affairs adviser to the Sandinista leadership. Lopez was in New York to consult with Mexican and Canadian officials who held weekend talks with Secretary of State Alexander M. Haig Jr.

Kirkpatrick said Lopez had requested the meeting, which she said she had cleared with the State Department, because he "wanted . . . a clarification from me" of Haig's announcement of a five-point proposal for peace in the region. Lopez, Kirkpatrick said, wanted to know if Haig "was serious when he proposed opposition to the importation of heavy weapons" in Central America. "I said yes, I thought it was serious," she said.

The meeting was the first known high-level contact between the U.S. and Nicaraguan governments since reports last week that President Reagan had approved a CIA covert action plan against Nicaragua. Kirkpatrick said she also had met with Lopez several months ago.

Borge's remarks to several foreign journalists came as Nicaragua entered its fourth day of a "state of emergency" that suspended constitutional guarantees in the face of what Borge termed "serious indications" of possible terrorist attacks and "military aggressions" against the 32-month-old regime.

U.S. officials frequently have alleged that much of the arms traffic to insurgents fighting against the U.S.-backed government in El Salvador is conducted by Nicaragua in and around the Gulf of Fonseca, on the Pacific coast, on which El Salvador, Honduras and Nicaragua border.

According to one usually well-informed source, at least one of the Nicaraguan boats appeared to have been returning to Nicaragua from the other side of the gulf when the incident occurred.

Yesterday's shootout in Zelaya Province, reported by the Nicaraguan Defense Ministry, appeared to be the latest in a series of confrontations between Sandinista troops and antigovernment guerrillas reportedly receiving covert U.S. support.

Despite such action in outlying border areas and fears of terrorist incidents such as the bombing of Managua's airport earlier this year, life in Nicaragua's capital city remains calm and there are few signs of serious unrest or destabilization.

The military presence on the streets, except for extra guard details on overpasses and bridges, is not especially higher than normal in this country full of newly recruited young men and women in olive drab. Around military installations such as the garrison near the Intercontinental Hotel there are a few new tank traps and simple barricades thrown up as extra traffic control and security precautions.

Restaurants and night clubs are open and traffic is heavy on most city streets.

But Nicaragua's leaders nevertheless remain conspicuously preoccupied with what they say they see as a continued and growing threat to their revolution.

U.S. officials have said that Nicaragua makes serious discussions virtually impossible because it refuses to admit that it gives material and logistical support to Salvadoran guerrillas as charged by the Reagan administration.

Borge repeated both the government's denial of its ability to control whatever arms trafficking may be going on and a frank admission of the Sandinistas' ideological sympathies with the Salvadoran insurgents.

Sandinista leaders have suggested, however, that the issue of El Salvador should not remain an obstacle to talks with the United States.

"Why is it so difficult to negotiate with us," Borge said, "and so easy for Kirkpatrick to negotiate with a Pinochet"--a reference to Chile's right-wing president, Augusto Pinochet. "If Hitler came back to life," Kirkpatrick "would negotiate with Hitler. But with us it is difficult to negotiate despite the fact that we are the ones who have practically taken the initiative for negotiation."

Kirkpatrick said later that she could "say for the record that I have spent three times as much time with Lopez as I have with General Pinochet."

U.S. Ambassador Anthony Quainton, who arrived here earlier this week and has not yet presented his credentials to the government, said today that his presence should be taken as an indication of Washington's continued willingness to maintain a dialogue with the Sandinistas.

"I'm here to explore all elements of our relations which are on the agenda and which divide us," Quainton said.