Israeli artiliery units pounded Palestinian strongholds in southern Lebanon today and Prime Minister Menachem Begin warned of further retaliation to "bloody aggression" following a guerilla rocket attack on a norther Israeli town from across the border.

One civilian was killed and six were injured when a salvo of Soviet-made Katuysha rockets fell on Qiryat Shemona in the northern tip of Israel less than five miles from the Lebanese frontier.

The attacks drove thousands more Israelis into bomb shelters and damaged a string of apartments which took a direct hit on the roof, Israeli military authorities said.

It was the first shelling of Qiryat Shemona-which in years past was the object of frequent attacks by Palestinian guerillas-since September 1977, and it appeared to signal the beginning of a new cycle of Israeli retaliations and Palestinian counter-retaliations.

After visiting the shelled area, Defense Minister Ezer Weizmen said, "The shelling was a reminder of things we'd begun to forget in the quiet reigning in the north the past months, but after due consideration and evaluation we shall arrive at decisions and carry them out."

On Wednesday, Israeli warplanes attacked suspected Palestinian training bases in three locations in Lebanon, apparently in response to Monday's bombing of a civilian bus in Jerusalem.

The air strike prompted a condemnation by the U.S State Department, which said in a statement that the retaliatory raid represented an "rscalating spiral of violence."

Begin today took offence at the U.S. statement. "It is an unjest statement," he declared. "We do not accept it. It is unjust because it makes no distinction between an act of bloody aggression and our legitimate act of national self defense."

Speaking at a luncheon meeting with foreign reporters here, the prime minister siad, "From time to time, ther have been attacks. People have been killed. Children have been hurt, and then there is an announcement from the [the Palestine Liberation Organization] in the Beirut, saying: "We did it. We claim responsibility."

"So we know where the responsibility lies. We know where the people who give these commands are," Begin said, his voice revealing controlled anger.

"I cannot divulge to you how many murdered attacks we have prevented from being carried out," the prime minister said." "In this generation, in which millions of Jews were dragged to wanton death , in which the world did not come to the rescue. . . we see bloodshed. In our generation, it is absolutely inconceivable that those who shed it can escape with impunity."

Asked whether a see-saw round of Palestinian and Israeli army attacks had begun Begin said, "Don't ask me to divulge to you our plans. We have to fulfill our duty to the Israeli people. . . you will have to rely on those who have to take these decisions."

Army officials said five Katuysha rockets fell yesterday in the vicinity of Qiryat Shemona. The Katuysha, a 122-mm rocket, has a range of about 15 miles and is considered by military experts to be an effective missile against "area targets" such as towns.

Army officials said the rockets were fired from Nabitya and Kaukaba, inside Lebanon. Nabitya was described as one of the strongest centers of Fatah, the main guerilla arm of the PLO. Nabitya is about 12 miles northwest of Qiryat Shemona, which has a population of about 25,000.

Qiryat Shemona, which over the years has been one of the most shelled towns in Irael, has developed a network of bunkers and has a sophisticated civil defence system. Many of the town's residents were asleep at the time of the 6:55 a.m. shelling, but others were on their way to work and were hit by shrapnel.

The lone fatality was a 23 -year-old Israeli cabinetmeaker who had arrived in the town the day before for reserve army duty.In addition to the six wounded, five children were hospitalized for shell shock.

Army officials said Israeli artillery units shelled the two Palestinian positions in Lebanon for about 40 minutes, beginning at 7 a.m. At nine a.m. the guerillas reportedly fired again on the town, and the fire was returned.

Throughout Israel, security had been intensified in the wake of a rash of bombings, most of them in Jerusalem.Special units of trackers with dogs have been searching villages on both sides of the west bank border, and army security officials reportedly have been interrogating suspected terorists.

Patrols have been stepped up in Jerusalem, particularly traditional targets such as the approaches to the old city.