GAZA CITY, Gaza Strip ? Palestinian militants forced open a border gate Friday between Egypt and Gaza, letting hundreds of people pour across despite warning shots from Israeli helicopter gunships.

At least 600 people – mostly students and patients trapped at the border in the weeks the Rafah crossing was closed – passed freely over the frontier. Six Palestinian militants stood by, periodically firing in the air, witnesses and Palestinian security said.

Also Friday, the United States pledged $50 million for Palestinian refugees, while Palestinian President Mahmoud Abbas urged Washington to pressure Israel to end its military offensive in the Gaza Strip.

Abbas told Secretary of State Condoleezza Rice in a telephone call that he was making every effort to end the Gaza crisis, the Palestinian leader’s office said.

The United States donated the money to the U.N. Relief and Works Agency to aid Gaza Strip and West Bank residents impacted by the fighting, U.S. Assistant Secretary of State David Welch said after meeting Abbas on Friday.