GAZA CITY, Gaza Strip — Israeli tanks and bulldozers pushed deep into the southern end of the Gaza Strip early yesterday morning in an incursion that left eight Palestinian Arabs dead, including a 12-year-old boy.

Backed by helicopters and missile-armed drone aircraft, about 50 tanks and bulldozers entered the strip at dawn yesterday near the Rafah border crossing with Egypt, witnesses said.

The tanks moved about five miles into Gaza, taking up positions near the long-shuttered Gaza International Airport and cutting off the main highway connecting Rafah with the rest of the Gaza Strip.

A series of airstrikes and tank attacks killed eight and wounded at least 26 Palestinian Arabs, the director of Rafah’s Abu Youssef Al Najar Hospital, Ali Moussa, said.

The tanks remained in position late last night, conducting house searches and combing the area for tunnels used to smuggle weapons from Egypt, an Israeli army spokeswoman said.

The Rafah area is riddled with tunnels linking Gaza with the Egyptian border town of Rafah. Israeli officials have long accused the Egyptian government of turning a blind eye to the weapons flow.

On June 25, Gaza militant fighters used a similar tunnel to stage a crossborder ambush that killed two Israeli soldiers and took a third hostage. Israel closed the Rafah crossing, and staged regular airstrikes, tank offensives, and artillery bombardments that have killed more than 150 people in Gaza.

Among yesterday’s casualties were two members each from the armed wings of Islamic Jihad and Hamas, officials said. Anis Abu Awad, 12, was killed by a tank shell, hospital officials said.

Since the start of the Israeli offensive six weeks ago, most of the Israeli army incursions have focused on the middle and northern part of the Gaza Strip, targeting areas from which militants regularly launch rockets toward southern Israeli towns. Yesterday’s offensive is the deepest Israeli push so far into southern Gaza.