GAZA CITY (CNN) -- Armed with rocket-propelled grenades, Hamas militants blew open a gate Friday on the border between Gaza and Egypt, allowing hundreds of people to cross into Gaza.

Militants wounded an Egyptian officer in the raid on the Rafah crossing, The Associated Press reported.

People streamed through the open gate, and the atmosphere grew tense as Israeli attack helicopters hovered over the area.

At the time, some 500 people were inside a lounge in a terminal on the Egyptian side of the border, according to witnesses and security sources.

The people were awaiting deportation back to Gaza because they lacked the proper paperwork.

The crossing has been closed since June 25, when three groups of Palestinian militants, including Hamas' military wing, captured an Israeli soldier.

Israel sent forces into Gaza and clamped down on residents' movements after the capture of Israeli Cpl. Gilad Shalit, 19, and the killing of two of his colleagues.

Hamas and other militants have demanded a swap for Palestinian prisoners in Israeli jails, but Israel has refused.

In other developments, the Israel Defense Forces said it withdrew some troops from central Gaza on Friday after they completed "their activities in the area" but said forces remained in southern Gaza.

Israel also says it wants to stop Palestinian militants from firing rockets from Gaza into Israeli towns and villages.

Four Israelis were treated for shock after militants' Qassam rockets struck the border town of Sderot on Friday, the IDF said.

The Israeli army said it hit more than 30 armed militants overnight in land and sea attacks, targeting seven groups that the military asserted were plotting against Israeli troops. The fate of the militants was not immediately known.

Military action on Thursday included a missile strike aimed at the Palestinian Foreign Ministry headquarters in Gaza City.

Witnesses and Palestinian security sources said 10 people were wounded and the building's fourth and fifth floors were hit.