U.S. Ambassador Lawrence Pezzullo returned here today, bringing "the word of my president that we want to maintain very intimate and friendly relations" with Nicaragua's new government.

Interior Minister and Sandinista leader Tomas Borge, who met Pezzullo at the airport, told him Nicaragua wants the same.

"We want to have permanent relations," Borge said. "You are welcome in Nicaragua."

Pezzullo arrived on a U.S. Air Force plane bringing 25 tons of food and medical assistance he said were President Carter's "personal expression of good will to the people and government of Nicaragua." Just 10 days ago he was recalled by Washington when a temporary successor to ousted president Anastasio Somoza refused, for a time, to hand over power to the junta.

Other U.S. planes have been carrying as much as 120 tons of food here daily, for a total of $3 million in emergency assistance over the past month.

Pezzullo said there is more where that came from, and indicated the United States is willing to supply other forms of economic aid that "coincide with [the Nicaraguan government's] own plans."

tthe U.S. Embassy said Pezzullo, who was appointed to Nicaragua serveral months ago but pointedly did not present his credentials to Somoza's government, would do so to the new administration this week.

Borge's welcome was surprisingly warm, coming from a man of radical left politics who has been a harsh critic of "Yankee imperialism." But the new Nicaraguan government has repeatedly insisted it wants friendly ties, and desperately needs help, from all nations of the world.

Thursday, when two members of the civilian government junta made a state visit to Cuba, President Fidel Castro publicly challenged the United States to a contest over who could be more helpful in rebuilding war-torn Nicaragua.

Sixty Cuban doctors and paramedics arrived here last week, and Castro promised to send hundreds of doctors and teachers if they are needed.

In a press conference on his return from Havana last night, junta member Alfonso Robelo said he would head a mission Monday to Venezuela and that junta member Sergio Ramirez would travel to Washington at the end of the week.

"We want to explain our situation, Robelo said, "so that our voices can be heard in the Arab world, in Western Europe, in the socialist countries, in Japan. We want to explain our problems to the whole world and show them the figures. We need the solid help of everyone.

"We want friendly relations with all countries," Robelo said.

Robelo said the junta plans to ask Latin America petroleum producers, including Venezuela, Ecuador and Mexico, for two years' oil supplies on special terms until the country is back on its feet.

Not only did the Somoza government leave Nicaragua $1.3 billion in debt, the junta has also charged that former officials cleaned out government safes and bank accounts before they fled. Most of the country's industry is damaged in varying degrees and export crops that provide most of Nicaragua's income have been severely disrupted.

Both Robelo and Moises Hassan, the other junta member on the Cuba trip along with Sandinista guerrilla leaders, had high praise for Castro and the Cuban people.

While the visit was to honor the 26th anniversary of the official beginning of the Cuban revolution, Castro turned the day's ceremony into a celebration of the Sandinista victory in Nicaragua.

"The visit was not by invitation," Hassan said. "We wanted to go and participate, to show our feeling, our appreciation and our respect for the Cuban people.

"Maybe it's hard to understand," Hassan said in reference to concern over close Nicaragua-Cuba ties, "but if you think about it without politics, we have had a hard time here. While some countries were giving [Somoza] bombs, the Cuban people always showed solidarity and we appreciate it."

While both Cuba and the Sandistas strongly denied early U.S. charges that Castro was supplying weapons and men to fight in Nicaragua, Cuba, along with many other countries, supplied training, logistical support and facilitated arms purchases from other countries, Sandinista sources have said.

"Independent of the fact that some countries might interpret it badly," Hassan said, "we know that if we could count on [Cuban] support during the long battle, we can count on it now."

Hassan said all Latin American presidents would be invited to Nicaragua in the near future.

"Even those who haven't been our friends, those who have been accomplices of Somoza, and those who stood by and watched" would be invited, Hassan said. "We're not rejecting the possibility that they'll change.

"We are open to all," he said, "and we don't want to block relations with anyone. If there are problems, they won't come from us."