A round of hit-and-run raids by counterrevolutionary guerrillas hiding in these rocky hills has pushed Nicaragua's Sandinista leaders to what appears to be a new level of anger and concern over the campaign against their rule.

The latest upsurge in sporadic attacks has seemed particularly worrisome here because it is taking place in villages and farming hamlets of Matagalpa province, as close as 70 miles northeast of Managua, the capital.

Most previous combat since the attacks accelerated last summer has taken place along the mountainous border with Honduras, to the north of here, or in isolated stretches of Zelaya province that slope from the border mountains down to the Atlantic coast.

A drive through several villages in the region indicates that the attacks remain isolated and small-scale, particularly compared to victory claims on the counterrevolutionaries' 15th of September Radio or to the Sandinistas' reports of an invasion from across the border. But several sources underlined that the attacks are important because they are nearer to the capital and in an area far less isolated than previous battlefields.

"It is not so much what is happening as where," said a diplomat in Managua. "It has moved to what was always seen to be--indeed what is--the central province."

Nicaraguans encountered along the dusty roadway here said most local peasants fear the antigovernment guerrillas but also fear retribution by the Nicaraguan Army if it appears the commandos have received help or cooperation. There is no sign of broad popular support for the counterrevolutionaries, they said. But they added that the commandos must have some clandestine support to remain in the area without running out of supplies or being denounced.

A woman interviewed in her country store at the nearby village of San Ramon said reports of repeated attacks began circulating at the end of the first week of March. This would mean the guerrillas have succeeded in remaining present and active here for more than two weeks.

Spokesmen for the main counterrevolutionary group, the Democratic Nicaraguan Front, have said in Miami that their troops have been encamped around the town of Rio Blanco, 40 miles east of here, for more than a month.

Against this background, the Sandinista government has taken several steps demonstrating its concern. In the most prominent, Deputy Foreign Minister Victor Tinoco spelled out complaints in an emergency meeting of the U.N. Security Council yesterday. He blamed the United States and Honduras for what he called "massive infiltration" across the border creating "a qualitatively different situation."

The United States and Honduras rejected the charges. Their spokesmen have sought to portray the recent surge in attacks as the outcome of popular discontent with the 3 1/2-year-old Sandinista revolution.

Defense Minister Humberto Ortega said earlier this week that 1,200 rebels have invaded Nicaragua in recent weeks. Most remained in the border mountains of Jinotega and Nueva Segovia provinces, he added, but 200 moved down into the Matagalpa region. Answering questions in New York, Tinoco raised the number of those in Matagalpa to 400 or 500.

Ortega's Defense Ministry reportedly dispatched a highly trained special Army battalion to the area. This represents a break with past practice that has kept the 22,000-man Army away from most fighting in favor of the more than 10,000 ready reserves.

An Army unit in this village was seen waiting in a truck, apparently preparing to move out on patrol to a more distant trouble spot. Soldiers carried full packs and AK47 assault rifles, general issue for Nicaragua's Popular Sandinista Army. Another truck nearby carried two 106-mm recoilless rifles.

As in previous instances, Ortega and Tinoco warned that the sedition could lead to a conflict with Honduras, closely allied with the United States and the recipient of increasing U.S. military aid. They charged that mortar fire from Honduran territory was directed at the Nicaraguan town of Santo Tomas del Nance yesterday.

Interior Minister Tomas Borge, at a news conference today, played down the military significance of the latest fighting. He asserted that foreign news reports in recent days have exaggerated its scope and said the attacks were designed to generate the impression--false, he said--of unrest here rather than of attacks from U.S.-financed counterrevolutionaries that the government says are its real problem.

Borge said the United States is seeking to promote the idea that Nicaragua is the scene of a civil war to create a counterbalance to the war in El Salvador. He said that would open an opportunity for bargaining what he called U.S. support for the guerrillas in Nicaragua against what the United States alleges is Nicaraguan support for the guerrillas in El Salvador.