BOURJ AL-MULOUK, Lebanon — Israel launched its deepest ground strike into Lebanon today, claiming it killed 10 Hezbollah guerrillas and captured five in the northeastern city of Baalbek, while nearby air raids killed at least 15 civilians.

Israeli warplanes also attacked a Lebanese army base in the southern part of the country, killing three soldiers, a security official said.

Hezbollah guerrillas hit back, firing a heavy barrage of at least 84 rockets at towns across northern Israel, wounding at least seven people, Israeli rescue services said. Israel medics said one of the rockets hit near the town of Beit Shean, the deepest rocket strike into Israel so far.

Witnesses in Israel also reported that a Hezbollah rocket hit the West Bank for the first time, striking between the villages of Fakua and Jalboun, near Beit Shean. The strike caused no injuries.

Lebanese security officials said Hezbollah had fired more than 300 rockets since dawn today. The discrepancy in the number of launches could not immediately be reconciled.

TIKRIT, Iraq — A U.S. soldier testified today that four of his colleagues accused of murdering three Iraqis during a raid threatened to kill him if he told anyone about the shooting deaths.Pfc. Bradley Mason, speaking at a hearing to determine whether the four must stand trial, also said that their brigade commander, a veteran of the 1993 "Black Hawk Down" battle in Somalia, told troops hunting insurgents to "kill all of them." Mason is not one of the accused.The alleged killings May 9 near Samarra, 60 miles north of Baghdad, have dealt another blow to the reputation of U.S. soldiers over their conduct in Iraq and fueled anger against their presence.U.S. soldiers and Marines have been accused of a string of civilian deaths in Iraq, including the alleged massacre of dozens in Haditha. Another hearing is scheduled later this month over allegations that five U.S. soldiers raped and killed a 14-year-old girl.Mason testified that Spc. William B. Hunsaker threatened him a day after the alleged killings. He said he was accosted by Staff Sgt. Raymond L. Girouard and Pfc. Corey R. Clagett on May 29 when he was on his way to the Criminal Investigation Division.Asked what was said that was of a threatening nature, Mason replied that Girouard told him: "'If you say anything, I'll kill you.' I took them pretty seriously."