At least three people were injured on Tuesday in clashes between Egyptian police and pro-Palestinian activists trying to get a relief convoy into the Gaza Strip, witnesses said.
Some 500 activists belonging to the convoy - led by charismatic and outspoken British MP George Galloway - broke down the gate at the port in El-Arish to protest against an Egyptian decision to ship some of the goods through Israel.
They blocked the two entrances to the port with vehicles, and clashed with police. A policeman and two protesters were hurt in the violence.
The protests were sparked by an Egyptian decision to allow 139 vehicles to enter Gaza through the Rafah border crossing, about 45 kilometres from El-Arish, that requires 59 other vehicles to go via Israel.
Talks in which Galloway and a delegation of Turkish MPs sought to change the Egyptians' minds proved unsuccessful.
The convoy of nearly 200 vehicles arrived in the Mediterranean town on Monday after a dispute with Cairo on the route.
The arrival came after a bitter dispute between its organisers and the government, which banned the convoy from entering Egypt's Sinai from Jordan by ferry, forcing it to drive north to the Syrian port of Lattakia.
Cairo accused convoy organisers of trying to embarrass Egypt, which has refused to permanently open its Rafah border crossing with Gaza after the Islamist Hamas movement took control of the Palestinian enclave two years ago.
Israel and Egypt have severely restricted travel to and from the Gaza Strip since Hamas seized power there in June 2007, after winning Palestinian legislative elections in 2006.
Hamas' takeover of the impoverished and densely populated territory led to an Israeli blockade that allows in only very basic supplies. Gaza was devastated in a war last winter between Hamas and Israel.