Two U.S. Marines assigned to guard duty at the Marine Barracks here have been arrested on charges that they tossed two canisters of smoke and tear gas into a Capitol Hill bar for homosexuals, an incident that prompted strong criticism of city and Marine officials from gay leaders.

Police charged Pfc. David H. Jenkins II, 18, and Pfc. John W. Davidson, 23, on Monday with felonious destruction of property after the two told police they had carried out the attack at the Equus bar and restaurant, 639 Pennsylvania Ave. SE, as a prank, said Det. John F. Rinkenberg of the First District.

The two could receive up to 10 years in prison and a $5,000 fine, if convicted on the charge. They were released in the custody of their superiors Monday after they were formally charged in a brief hearing before a D.C. Superior Court judge.

Marine officials, who said immediately after the incident there was no proof Marines were involved, had no comment yesterday on the arrests.

Shortly before 2 a.m on June 13, two men with close-cropped hair entered the Equus through a back door and tossed the smoke and tear gas canisters into the bar, forcing about 50 patrons, coughing and gagging, to evacuate.

The bar closed for nearly three days after the attack, and Equus owners estimated the damages at more than $5,000.

In an attack on the Equus last August, a group of Marines stormed into the bar, assaulted one of the owners and broke windows. No charges were brought in that incident.After the most recent incident, gay leaders criticized Mayor Marion Barry for not putting more pressure on police to arrest the Marines involved in last August's incident.

Equus is not far from the Marine Barracks at 8th and I streets SE, and the Marines and gays have had an increasingly tense coexistence in recent years.

Marines have complained that gays have tried to pick them up for dates and the soldiers have expressed disappointment that the bar, which had been a Marine hangout under previous owners, was transformed into an establishment for gays.

Yesterday, Denny Graham, part-owner of Equus, said the arrests might be an encouraging sign.

"I was very heartened that they acted as quickly as they did and that they actually did find somebody this time," Graham said. He said police told bar owners that Marine officials had cooperated fully in the investigation.

Graham said he wants police and Marine officials to continue their investigation, because he is convinced that more than two men were involved. "They got away too fast," he said, "there had to be somebody waiting for them in a car." He also said he wanted police to trace where and how the canisters used in the attack were obtained.

Police said they believe the canisters came from the barracks, but the suspects have denied that they obtained them there.

Det. Rinkenberg said the investigation is continuing and that there is insufficient evidence to arrest anyone else.

He said the investigation was aided by an anonymous phone caller who supplied police with a name that ultimately led officers to the two men who were arrested.

Both were questioned by Marine officials before surrending to police.

Jenkins, of Fayetteville, N.C., has been in the marines for 1 1/2 years. Davidson, of Yakima, Wash., has been in for nearly a year, said a Marine spokeswoman. Both men help provide security as guards at the barracks, where 800 Marines are stationed.