BEIRUT, Lebanon- – Israel launched a major attack deep into Lebanon, and Hezbollah said its guerrillas were fighting Israeli commandos trapped inside a hospital in the eastern city of Baalbek early Wednesday.

The Israeli army would not comment on the operation in the ancient city, which was once a Syrian army headquarters some 80 miles north of Israel. The Web site of the Israeli daily Haaretz reported that “helicopters put down IDF (military) commandos near Baalbek,” without adding details.

The ferocity of the battles in Baalbek and across southern Lebanon on Tuesday, the determination of the Israelis to keep fighting and the minimal diplomatic progress toward a cease-fire indicate the 3-week-old war is more likely to escalate than end.

Hezbollah’s chief spokesman, Hussein Rahal, said that Israeli troops landed near Dar al-Hikma Hospital and fierce fighting was raging after more than one hour.

“A group of Israeli commandos was brought to the hospital by a helicopter,” Rahal said. “They entered the hospital and are trapped inside as our fighters opened fire on them, and fierce fighting is still raging.”

Rahal said Hezbollah was using automatic rifles and rocket-propelled grenades and Israeli jets were attacking the surrounding guerrilla force with rockets.

He dismissed reports “untrue” that the Israeli commandos managed to snatch some patients from the hospital and spirit them away in helicopters. Hezbollah’s capture of two Israeli soldiers in a July 12 cross-border raid triggered the ongoing Israeli offensive in Lebanon.

Witnesses said the hospital was hit in an Israeli air strike and burning.

Baalbek is a city with spectacular Roman ruins as well as the barracks of the Iranian Revolutionary Guards when they trained Hezbollah guerrillas there in the 1980s.