A seven-hour standoff during which a man allegedly fired more than 60 rounds of ammunition from a house in Bladensburg, keeping Prince George's County police pinned down, ended early yesterday with the man's surrender. There were no serious injuries.

Police charged John Carr, a 49-year-old printer who, a relative said, had not worked for several years, with four counts of assault with intent to murder in connection with shots allegedly fired at four county police officers, according to police spokesmen. Carr was jailed in lieu of $100,000 bond.

For the past few days, Carr had been staying with his brother, James, at 5617 Emerson St., Bladensburg, where the incident occurred, police said. Police said they found five rifles, a helmet, gas mask, two handguns and ammunition in the house.

Carr's sister-in-law, Janice Carr, said yesterday that she and her family left their home shortly after 6 p.m. and went to a neighbor's house after Carr allegedly threatened them with a weapon. She said Carr had been upset recently because his best friend had died and because he had had to move from the home where he had been living for the past 15 years. She added that he was staying with her family temporarily.

Janice Carr said her husband, James, tried unsucessfully for several hours to persuade his brother to leave the house and said he would help him check into a motel. But, Janice Carr said, "he wouldn't listen . . . he said he wasn't leaving, he wasn't coming out."

James Carr called police from the neighbor's house at about 8 p.m. and asked for help in getting his brother out of the house, according to Janice Carr. She and the neighbor, Gloria Jones, said police advised that if Carr wanted police to get his brother out of the house, he would have to go to a nearby police station to get a court order to have him arrested or committed to a hospital. Carr declined to do so, the women said.

After failing to persuade his brother to leave the house, Carr apparently decided to get the order and resummoned police to his house, Jones said, and four officers arrived and spoke to James Carr on the sidewalk outside his house. James Carr got into his car and headed for the police station, but as the police began to return to their cruisers, John Carr allegedly opened fire on them, the police spokesman said.

The police officers returned fire and then fell to the ground for cover, a spokesman said. A special county police negotiator and a police emergency response team arrived, and the four officers were rescued by an armored personnel carrier owned by the U.S. Park Police, police said. County police blocked access to the neighborhood, called all residents in the area and advised them to turn off their lights and remain in the rear of their homes until the incident was over, police said.

During the standoff, John Carr allegedly fired 60 shots from the house. No shots were fired by police after the initial exchange of gunfire except to extinguish a street light, a spokesman said.

After police were held at bay for more than six hours, tear gas was fired into the house and Carr surrendered about a half-hour later at about 5:55 a.m. police said.