An Egyptian border guard was killed and at least a dozen Palestinians wounded in a shooting scuffle along the Gaza Strip border.

One official said Wednesday that the border guard was shot dead by a Palestinian sniper while Gazan youths hurled stones across the border at the Egyptian security forces.

Egyptian forces opened fire on Palestinians who were pelting them with rocks from the other side of the border over frustration that an aid convoy had been delayed.

Gaza's Hamas rulers called for the protest earlier over the delay of an international aid convoy at the nearby Egyptian port city of El-Arish, but soon lost control of the situation as hundreds of youths began hurling rocks across the border at the guards.

Hamas police fired shots to disperse the crowd and shots were also heard from the Egyptian side the border. Palestinian health official Moawiya Hassanein said the injuries were from gunfire and tear gas.

The incident follows a late night clash between international pro-Gaza activists and Egyptian security clashed at the nearby Mediterranean port of El-Arish when Egypt refused to allow part of the convoy to enter its territory and move on to Gaza.

More than 50 activists and over a dozen members of the security forces injured. Activists briefly seized some policemen as well.

The clashes add to the embarrassment of Egypt, which has come under fire from Arab and Muslim groups for cooperating with Israel in its 28-month blockade of the impoverished territory. The blockade was imposed after Hamas violently seized control of the territory from the forces of Palestinian President Mahmoud Abbas.

More than 500 international activists accompanied the convoy organized by the British-based group Viva Palestina, bringing tons of humanitarian supplies, as well as vehicles, to Gaza. The group includes British, American, Jordanian and Turkish activists and lawmakers.

The scuffles at the port broke out late Tuesday at al-Arish port building when authorities told the organizers that out of the nearly 200 vehicles, some 59 can't enter Gaza through Egypt, but must go through Israeli terminals.

A security official said the vehicles in question are carrying pickup trucks, sedans, generators and other equipment, which are not allowed to pass through the Egyptian crossing at Rafah and had to go via Israel. Only medical aid and passengers are allowed through, the official said.

British MP George Galloway told Sky News television that the activists were negotiating with authorities and refusing to leave behind their vehicles.

"We refused this because it's a breach of the agreement which we reached," he said. "It is completely unconscionable."

Foreign Ministry spokesman Hossam Zaki said the rules were clear from the start, and accused the activists of coordinating with Hamas to create problems. He said the private automobiles are not considered humanitarian goods, and must enter from Israel.

"We didn't mislead anyone. They have their interests ... and they want to make up problems and clash with Egypt," he told The Associated Press.

"We are activists. We condemn the Israeli siege to start with. We will only enter through an Egyptian-Palestinian crossing," said Wael al-Sakka, a Jordanian activist.

Alice Howard, a spokeswoman for the group, said organizers were negotiating with an Egyptian security official, who said he would come back with answers.

But instead, 2,000 riot police returned, spraying the activists with water cannons, and hurling rocks.

Television reports showed images of both riot police and activists hurling stones at each other and said clashes began when angry protesters attempted to leave the port area and were driven back by riot police.

Howard, speaking from London, said more than 50 activists were injured in the scuffle, including to the head and neck. The group's Web site showed images of injured activists.

An Egyptian security official said the activists used two trucks to block the port gates, burned tires, and briefly detained a police officer and four of his men. They were later released, some with broken ribs.

The official was speaking on condition of anonymity because he was not authorized to speak to the media.

Al-Sakka, the Jordanian activist, said the police charged a peaceful sit-in at the gates of the port. He said the group was not allowed to get out of the port building, denying government claims they have took control of the premise.

The Egyptians were too high-strung. The police is the reason for the tension, al-Sakka said.

He said six activists were detained, including Americans and British citizens.

The security official said five were detained, but didn't identify them. U.S. embassy officials did not immediately have information on the arrests.