GAZA CITY, Gaza Strip — Israel expanded its fierce air assault on rocket operations in the Gaza Strip on Saturday, striking Hamas government and security compounds, smuggling tunnels and electricity sources after an unprecedented rocket attack aimed at the holy city of Jerusalem raised the stakes in its violent confrontation with Palestinian militants.
Israeli aircraft also kept pounding their initial targets, the militants' weapons-storage facilities and underground rocket-launching sites. The Israeli military called up thousands of reservists and massed troops, tanks and armored vehicles along the border with Gaza, signaling a ground invasion of the densely populated seaside strip could be imminent.
Israel launched its military campaign Wednesday after days of heavy rocket fire from Gaza and has carried out some 700 airstrikes since, the military said. Militants, undaunted by the heavy damage the air attacks have inflicted, have unleashed some 500 rockets against the Jewish state, including new, longer-range weapons turned for the first time this week against Jerusalem and Israel's Tel Aviv heartland.
Israel has slowly expanded its operation beyond military targets and before dawn on Saturday, the Gaza Interior Ministry reported, missiles smashed into two small Hamas security facilities as well as the massive Hamas police headquarters in Gaza City, setting off a huge blaze that engulfed nearby houses and civilian cars parked outside. No one was inside the buildings at the time.
The Interior Ministry said a government compound was also hit as devout Muslims streamed to the area for early morning prayers. So, too, was a Cabinet building where the Hamas prime minister received the prime minister of Egypt on Friday.
In southern Gaza, Israeli aircraft went after the hundreds of underground tunnels militants used to smuggle in weapons and other contraband from Egypt, people in the area reported. A huge explosion in the area sent buildings shuddering in the Egyptian city of El-Arish, 30 miles (45 kilometers) away, an Associated Press correspondent there reported. The tunnels have also been a lifeline for residents of the area during the recent fighting, providing a conduit for food, fuel and other goods after supplies stopped coming in from Israel days before the military operation began.