Gaza police in border crackdown

Palestinian forces are determined to stop illegal border crossings

Palestinian police have fired in the air to prevent stone-throwing crowds in southern Gaza from crossing into Egypt.

The border area has been the focus of chaotic scenes since Monday, when Israeli troops who had kept the border sealed for decades withdrew.

But the Palestinian authorities have promised to restore order.

Meanwhile, Israeli Prime Minister Sharon has pledged not to co-operate with Palestinian polls due in January if the militant group Hamas takes part.

The BBC's Alan Johnston in Gaza says the Israeli army used to keep huge numbers of people bottled up in Gaza, denying them permission to leave.

When the Israelis left, he adds, many Palestinians took advantage of a sudden opportunity to cross the unguarded border and visit the Egyptian side.

Egyptian troops helped block holes in the border fence

Palestinian Prime Minister Mahmoud Abbas vowed to stop illegal crossings after border police were brushed aside on Friday.

On Saturday about 1,500 troops were deployed along the border to try to restore order.

They fired shots in the air when Palestinians began to throw stones.

Palestinian and Egyptian troops have been blocking holes in the frontier fence.

Help needed?

The authorities on both sides are allowing people to cross to return home only.

I don't think they can have elections without our help Ariel Sharon

The clashes occurred as Mr Sharon threatened to withhold co-operation from the Palestinian election.

In remarks to journalists quoted by the New York Times, Mr Sharon said Israel would "make every effort not to help" if Hamas took part.

The prime minister - who is at the United Nations in New York - added that he did not think the Palestinians could have elections without our help".

He cited a refusal to remove roadblocks and checkpoints as possible steps the Israelis could take.

Palestinian chief negotiator Saeb Erekat urged Israel not to interfere with the election.

Mr Abbas has resisted disarming Hamas by force, as Israel has urged it to do.