Israeli tanks and infantry took up positions on the Egyptian-Gaza border Wednesday for the first time since Israel's withdrawal from Gaza last summer as the army pushed deeper into Gaza looking for smuggling tunnels.

Palestinian security officials said Israeli infantry and tanks moved into the border town of Rafah before dawn Wednesday and took over a swath of the Gaza-Egypt border, including an area close to the Rafah border terminal. The crossing has largely been closed since Hamas-allied militants captured an Israeli soldier in late June.

Israeli troops killed two Hamas militants as they approached army positions in Rafah Wednesday morning, the army and Palestinians said.

The army said Israeli forces were widening the scope of an ongoing operation in southern Gaza aimed at uncovering tunnels used by Palestinian militants to smuggle weapons into the Gaza Strip from Egypt. Two such tunnels were discovered in another area along the border early Tuesday morning, the army reported. Israel has charged that militants have smuggled large quantities of weapons over the border since Israel's unilateral withdrawal from Gaza last summer.

Troops carried out house-to-house searches and bulldozers leveled agricultural land near the border, the Palestinian officials said, speaking on condition of anonymity because they were not authorized to speak to the press.

According to a statement from the military wing of Hamas, one of the two dead was a senior militant involved in the June capture of Israeli soldier Gilad Shalit, the incident that sparked the current Israeli offensive in Gaza. Shalit remains in captivity.

In northern Gaza late Tuesday night, Palestinians reported that two Hamas gunmen were killed near the Jebaliya refugee camp during exchanges of fire with Israeli troops. The army said troops had killed one armed militant.

Palestinian President Mahmoud Abbas continued his efforts to end the political deadlock in the Palestinian Authority Tuesday, promoting the idea of a Cabinet of technocrats as a way to ease crippling Western sanctions. But he pledged not to force it on Hamas, and the Islamic ruling party was cool to the idea.