LOUISVILLE, Ky. (AP) _ A printing plant worker disabled by mental illness was able to legally buy the AK-47 assault rifle he used to kill seven former co-workers without revealing his mental problems, authorities said Friday.

Police said Joseph T. Wesbecker was armed with several semiautomatic weapons and hundreds of rounds of ammunition Thursday morning as he went from floor to floor at the Standard Gravure Corp.

Wesbecker killed seven people and injured 13 before killing himself. Three of the injured were in critical condition Friday.

Standard Gravure employees met with grief counselors when they returned to the plant Friday morning and several hundred later attended a Mass at the Roman Catholic Cathedral of the Assumption.

President Bush on Friday lamented the loss of life in the rampage, but said he still opposes legislation to ban possession of such weapons.

Bush in March banned the import of foreign-made assault rifles into the United States, including the Chinese-made AK-47. Howeer, possession of the weapon is not a federal offense and Bush has taken no steps toward proposing curbs on U.S. manufacture of such weapons.

Wesbecker bought the AK-47 on May 1 at Tilford's Gun Sales in Louisville, said Police Chief Richard Dotson.

Gun shop owner Jack Tilford said Wesbecker answered all eight questions properly on a federal Bureau of Alcohol, Tobacco and Firearms gun purchase form.

''He passed all the tests and obligations for purchasing firearms,'' Tilford said Friday.

One of the eight questions asked: ''Have you ever been adjudicated mentally defective or have you ever been committed to a mental institution?''

The form shows Wesbecker answered 'no' to that question. Tilford noted that gun shop owners have no way to check the validity of answers to that question.

Lt. Jeff Moody, police homicide commander, has said that Wesbecker had spent time - voluntarily - in mental institutions, including Our Lady of Peace in Louisville. Police would not reveal when he had been hospitalized.

Wesbecker, 47, was a pressman at the plant from 1971 until the company placed him on permanent disability leave last Feb. 2 because of mental illness, police said.

Relatives told police that Wesbecker was a manic depressive who had attempted suicide three times.

Bill Curley, agent in charge of the Louisville ATF office, said federal law prohibits firearms purchases only by people who have been committed to a mental health facility under court order.

Moody said four other guns were found during a search of Wesbecker's home, as well as the Feb. 6 issue of Time magazine turned open to a detailed article on similar shootings across the United States in the past two years.

Bush, during a interview with out-of-town reporters, was asked about Thursday's rampage.

''It is terrible and the loss of human life is horrible. But I have seen no evidence that a law banning a specific weapon is going to guard against it ...,'' he said. ''If you have somebody who is deranged, and I don't want to prejudice this poor soul, but if he was deranged, I'm afraid you're going to have incidents like this.''

Standard Gravure officials hired 15 counselors to help workers when they returned to the plant Friday morning.

''All of these people can be classified as victims,'' said Mark Ahearn, vice president of development for Seven Counties Services. ''We don't need people holding back their pain. Swallowing it won't do them any good.''

Standard Gravure President Michael Shea said almost 90 percent of the company's 360 employees were counseled in offices that had been cleaned up overnight. Bullet holes in walls and ceilings were the only physical reminders of the tragedy.

''Until it strikes home like it has for us, you don't realize how traumatic something like this can be,'' Shea said. ''I'm pleased to say that, so far, the counseling has gone very well.''

Pressman Tom Noonan said the workers were split up into groups, with some receiving one-on-one counseling.

''You just vented your feelings,'' Noonan said.

Outside the three-story building, some workers talked to reporters.

''I'm thinking seriously about looking somewhere else for another job. My nerves are shot,'' said pressman Steve Pate. ''If I go back in there, I'll be waiting for someone else to do the same thing and I can't handle that.''

Forklift operator Bernard Williams said he was going to take a week's vacation.

''I'm not ready to come back because of everything that's happened. Things like this could happen again,'' Williams said. ''I just don't feel like I can go in there and work.

''There are a lot of workers who have been traumatized by this. It's a shame that management treats people like dogs. They should treat employees like human beings instead of just a number.''

Shea refused to comment on complaints about working conditions and specifics on improved security measures being implemented at the plant. He said full production would resume Monday.

He also would not disclose Wesbecker's weekly disability pay or whether those payments were about to be stopped by the company, a claim co-workers have made in trying to explain the reasons for Wesbecker's rampage.

Many of the workers joined several of the victims' families at an hourlong Mass conducted by Archbishop Thomas Kelly. They hugged and wiped away tears during the service, which was also attended by Mayor Jerry Abramson and other local, state and federal officials.

''All of us gather in deep, profound sorrow. We come together to pray for those who are suffering pain and grief,'' Kelly said during the service attended by about 300 people.

Three of the wounded were in critical condition Friday at Humana Hospital- University of Louisville, including one man shot in the chest and leg who was back in surgery Friday afternoon.

The bloodshed started in the plant's executive offices on the third floor, moved down to the basement, then up to the first floor.

Wesbecker reportedly had made threats against the company, which prints newspaper inserts and Sunday newspaper supplements, but Shea said he did not know of any threats.

Wesbecker's weapons included the AK-47, two MAC-11 semiautomatic machine pistols, a .38-caliber handgun, a 9mm automatic pistol and a bayonet, said Dotson. Wesbecker carried a duffel bag full of ammunition.

The two MAC-11s were purchased in February, also at Tilford's.

Wesbecker was divorced twice in the last 11 years. He and his first wife had two sons, 22 and 26. Wesbecker and his second wife, Brenda, were also divorced, but they had been living together since 1987, Moody said.