Hundreds of Palestinians rioted and clashed with Israeli forces at checkpoints around Jerusalem on Friday after authorities blocked them from entering the city to mark the Ramadan holy month at Islam's third-holiest site.

Soldiers dispersed the crowds with stun grenades, tear gas, rubber bullets and water cannons. At one checkpoint, desperate protesters tried to scale Israel's massive concrete separation barrier with ladders.

Jerusalem police spokesman Shmuel Ben-Ruby said border policemen made six arrests. No injuries were reported.

The protesters were on their way to the Al-Aqsa mosque in Jerusalem. Friday is the weekly holy day for Muslims, and it is considered an honor to attend Friday prayers at Al-Aqsa during Ramadan. Tradition says Al-Aqsa is where the Prophet Muhammad, Islam's founder, ascended to heaven.

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About 170,000 people attended Friday's prayers, roughly half of them West Bank Palestinians with entry permits, Ben-Ruby said.

However, Israel did not allow Palestinian men under 45 to attend the prayers, citing security concerns. Younger men angry about not being allowed into the city threw stones at troops, he said.

Clashes were reported at four checkpoints around Jerusalem and one near Nablus, in the northern West Bank, where some 3,000 worshippers gathered at daybreak to make the long journey to Jerusalem.

At the Aram checkpoint on the outskirts of Jerusalem, people used ladders and rope to scale the 25-foot concrete separation barrier.

Witnesses said about 200 people made it over the barrier, but Ben-Ruby said none of the climbers made it into Jerusalem. Most were thwarted by the concrete and barbed wire, while some were arrested, he said.

Israel has been constructing the barrier along the frontier with the West Bank. Israel says the structure is needed to keep attackers out of the country. The Palestinians condemn the barrier as a land grab because it frequently juts into the West Bank.

Israel has built more than half of the barrier, which is expected to run for 437 miles.

Meanwhile in the Gaza Strip, the Israeli military stepped up its offensive, killing at least four people in a series of attacks.

The fighting brought the death toll in the offensive to 13 Palestinians, including a young girl, since Thursday.

The army has been carrying out an offensive throughout Gaza since June, when militants linked to the ruling Hamas militant group tunneled into Israel and captured an Israeli soldier. The soldier remains in captivity.

After a recent lull, the fighting has picked up in recent days. Israel TV said the operation in Gaza Friday was the largest there in weeks.

An Israeli aircraft attacked a car in the northern Gaza Strip, killing three Hamas militants, including a local commander, the group said. Witnesses said the force of the blast ripped the white sedan into two parts. The army confirmed it had carried out the strike.

In the southern Gaza Strip, Palestinian hospital officials said Israeli troops shot a 29-year-old woman outside her house in the village of Abassan.

The army said it had no information about a woman being shot. It reported killing one armed militant and wounding another in the same area around the same time.

The latest Israeli activity has been focused in the Abassan area, near the southern city of Khan Younis. An Israeli airstrike on Thursday killed six people, including two teenage civilians.