Washington area government officials, responding to an increasing number of gun-related homicides, called yesterday for tougher gun-control laws, including a ban on some assault weapons and stiffer penalties for people who commit crimes with guns.

The Metropolitan Washington Council of Governments, which endorsed a resolution backing the measures, will seek support for them in Congress and the Maryland and Virginia legislatures.

The action by the local government leaders reflects a growing sentiment for more gun control and marks increasing pressure on state legislators, who have begun passing stricter firearm laws in recent years. It is a signal, officials said, of increasing impatience with the area's homicides.

In the Washington area last year, more than 700 people were killed, nearly 75 percent of them with guns.

COG's adoption of the resolution, said Warren Graves, a District representative on the board, "will lend support to lawmakers at the federal, state and local levels as they seek to strengthen gun-control laws."

The move, backed by area police chiefs, also reflects continued polarization on gun-control issues between some law enforcement officials and the National Rifle Association, which has traditionally fought many gun-control measures.

In the past, police generally have had close ties with the NRA, which provides firearm training to departments throughout the nation and sponsors shooting competitions.

"In general, we have had some distancing from the NRA on gun-control issues in recent years," said Fairfax County Police Chief John Granfield, head of COG's Police Chiefs Committee. "It's happened because we have seen the need for additional controls . . . . We think that there are too many handguns out there."

Prince George's Police Chief David B. Mitchell agreed. "We are not for total prohibition," he said. "Our focus is not to disagree with the NRA as much as it is to support reasonable legislation that might save lives."

Wayne LaPierre, a spokesman for the NRA, said yesterday, "There is no doubt that some {law enforcement} organizations and police chiefs have come out against us. But on the whole I think the relationship is improving . . . . We've always had good relationships with the rank and file."

LaPierre said COG's resolution "represented little that is new. What they ought to be addressing is the backlog in courts and {the need for} prison space," he said.

Proposals supported yesterday by COG include a mandatory sentence for using a gun in a felony, a waiting period before the purchase of a handgun, and a ban on the manufacture and possession of some semiautomatic weapons.

In another vote, COG also endorsed increased federal funding for the District, which is being sought by Mayor Sharon Pratt Dixon to ease the city's budget deficit.

Gun-control advocates -- including Sarah Brady wife of former White House press secretary James Brady, who was wounded in an assassination attempt on President Reagan, and James Bias, whose son recently was gunned down in Maryland -- applauded COG's action. Bias attended the meeting.

"These firearms are designed for use in combat -- to mow down human beings -- and have no place on America's streets," Sarah Brady said.

Officials in the area have been struggling to reach a consensus on gun control.

The D.C. Council, which banned the sale of all guns in 1976, last year approved a gun-liability measure allowing victims or their families to sue assault-weapon merchants. However, the council later repealed it in an effort to help Dixon win aid from Congress.

Some District officials have argued that their ban on gun sales has been made ineffective by less stringent laws in Maryland and Virginia. About 70 percent of the guns used in District crimes are bought in those states, according to the U.S. Treasury Department's Alcohol, Tobacco and Firearms Division.

During the last two years, Maryland and Virginia have passed gun-control legislation.

Maryland passed legislation requiring seven-day waiting periods and background checks for those who want to buy certain military-type assault weapons. Gov. William Donald Schaefer is seeking a ban on military-style assault weapons. Mitchell said he and other police chiefs throughout Maryland plan to rally behind the governor at a meeting in Annapolis scheduled for today.

Virginia officials approved a measure two years ago requiring criminal background checks on buyers of some types of guns.

However, the Virginia House recently killed a proposal that would have required a three-day waiting period for the purchase of a handgun. Legislators are considering a bill to expand background checks to include buyers for virtually all firearms.

Mandatory prison sentence for use of firearm in felony.

Waiting period before purchase of gun.

No import, export, manufacture, possession or transfer of new semiautomatic assault weapons not designated for "sporting" uses.

No import of unassembled parts of prohibited weapons. STATE LEVEL

No manufacture, possession or transfer of new semiautomatic assault weapons not designated for "sporting" uses.

Registration of all legal weapons.

Detailed record-keeping of inventory and sales by gun dealers.

Licensing of gun dealers.

Mandatory prison sentence for using firearm in felony.