GAZA CITY, Gaza (CNN) -- Four Israeli soldiers were shot dead by Palestinian gunmen at a border crossing between Gaza and Israel early Sunday.

The Palestinian gunmen, who were dressed as Israeli soldiers, opened fire at the Erez crossing, prompting Israeli soldiers to fire back, killing three, the Israel Defense Forces said.

Four others were injured in the attack, according to Israeli sources.

It is the first deadly attack since last week's summit in Aqaba, Jordan, between Palestinian Prime Minister Mahmoud Abbas, Israeli Prime Minister Ariel Sharon and U.S. President George W. Bush.

It came just hours after radical and militant Palestinian groups pledged to continue their armed intifada against Israel.

Three militant Palestinian groups -- Hamas, the Islamic Jihad, and the Al Aqsa Martyrs Brigades -- claimed responsibility for the attack in a telephone call to journalists in Gaza. [...]