The United States has asked Israel to supply information on whether it has used U.S.-supplied "cluster bombs" in Lebanon in violation of longstanding agreements, State Department officials said yesterday.

Wat T. Cluverius, a deputy assistant secretary of state who has been handling Middle East negotiations, disclosed the U.S. inquiry as a House subcommittee approved $20 million in emergency aid to Lebanon.

Cluverius would not specify, under questioning by Rep. Paul Findley (R-Ill.), the legal or political consequences if Israel is found to have used the devastating projectiles, developed for U.S. forces in Vietnam, which release hundreds of steel shards from each grenade-sized weapon.

Press reports from Lebanon said cluster bombs were dropped on the Palestinian refugee camp of Bourj Brajneh near Beirut and the Armenian hospital at Aazzouniye in the hills over the Bekaa valley. According to Washington Post correspondent Jonathan C. Randal, who saw the anti-personnel bombs at the hospital last Sunday, no one was killed by them in the air attack there but three persons were severely injured when they picked up unexploded weapons.

About 22,000 cluster bomb projectiles were supplied by the United States to Israel in the early 1970s, on condition they be used only for "defensive purposes." Late in 1976 Israel reportedly promised the Ford administration the bombs would only be used against military, fortified targets and only if Israel were attacked by more than one country.

After reports that cluster bombs were used by Israel against refugee camps, farms and villages in early 1978, in the previous large-scale invasion of Lebanon, Israeli authorities informed Washington that a mistake had been made in using the weapons and promised to impose tighter restrictions.

The current Lebanese devastation was described yesterday by Rep. Lee H. Hamilton (D-Ind.), chairman of the House subcommittee, as a "carnage of enormous proportions."

Bradshaw Langmaid Jr., a deputy assistant administrator of the Agency for International Development, testified that around 600,000 people living in Beirut and southern Lebanon have been "directly affected" by the fighting following the Israeli invasion. This estimate includes those killed and wounded, as well as those made homeless, displaced or in need of food, water or medical supplies.

AID Administrator Peter McPherson, who was named as special coordinator for Lebanon disaster relief, said he will meet in New York today with U.N. Secretary General Javier Perez de Cuellar to launch the new U.S. effort.

The hearing of the House subcommittee touched off the first congressional exchange on Lebanon, with three members of Congress condemning Israel's invasion, one of them demanding that the Reagan administration threaten an aid cutoff to force an Israeli withdrawal.

Rep. Mary Rose Oakar (D-Ohio) said Reagan should follow a precedent set by former president Jimmy Carter in threatening to apply aid-cut provisions of the Arms Export Control Act in getting Israel to withdraw troops there in 1978.

Rep. Nick J. Rahall (D-W.Va.) also accused the administration of failing to rein in the government of Prime Minister Menachem Begin whose forces, he claimed, had killed nearly 10,000 people in Lebanon.

"It is apparently clear that no matter what Prime Minister Begin does, this country just will not oppose him," Rahall said in testifying to the subcommittee.

Several Democratic members said that humanitarian aid should be considered urgently but that questions of blame and the political-military situation should be set aside for future hearings.

"I hope we can eliminate any recriminations whatsoever," said Rep. Benjamin S. Rosenthal (D-N.Y.).

The Israeli invasion so far has aroused little debate in Congress, far less than when the Israeli Air Force last year attacked an Iraqi nuclear reactor near Baghdad. A small group of congressmen has introduced a resolution condemning Israel and asserting that U.S.-supplied military equipment may have been used in violation of American law.

Findley, who has frequently taken up the cause of Palestinians in Lebanon, claimed that 16,000 civilians had been killled during the fighting and said, "The lack of action to bring this fighting to a stop is appalling."