Jerusalem ? Hundreds of Palestinians fought with Israeli troops and used makeshift ladders to climb over Israel’s towering West Bank separation barrier Friday after being barred from entering Jerusalem to attend Ramadan services at Islam’s third-holiest shrine.

The apparently spontaneous outbursts at checkpoints around the holy city reflected Palestinians’ growing anger with the continued construction of the barrier and their frustration with Israeli restrictions keeping many of them out of Jerusalem.

Israeli forces dispersed the crowds with tear gas, stun grenades, rubber bullets and water cannons.

Israel killed six militants and wounded 15 in airstrikes today east of Gaza City, Palestinian security officials said. More than a dozen Israeli tanks also moved into the area, and security officials reported exchanges of fire between the Israeli forces and Palestinian gunmen.

The deaths brought to 19 the number of people killed in the last three days as Israel has pressed forward with an expanded offensive in Gaza. Most of them have been militants.

The violence at the West Bank checkpoints outside Jerusalem began Friday morning as hundreds of Palestinians tried to head to the Al-Aqsa mosque in Jerusalem for prayers. It is considered an honor to attend Friday prayers during the holy month of Ramadan at Al-Aqsa, where tradition says the Prophet Muhammad, Islam’s founder, ascended to heaven.

An Israeli border police officer and a Palestinian man scuffle at the Kalandia checkpoint, on the outskirts of Jerusalem. Palestinians trying to enter Jerusalem to attend Ramadan Friday prayers at the Al-Aqsa Mosque compound and Israeli troops clashed Friday at several checkpoints between Jerusalem and the West Bank.

About 170,000 people attended prayers Friday at the mosque, roughly half of them West Bank Palestinians with entry permits, Jerusalem police spokesman Shmuel Ben-Ruby said.

However, Israel did not allow Palestinian men younger than 45 to attend, citing security concerns. Angry at being barred, they threw stones at Israeli police, Ben-Ruby said.

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

At the Ram checkpoint outside Jerusalem, people used ladders and rope to scale the 25-foot-tall separation barrier. Other protesters propped an electricity pylon against the concrete wall in an effort to scale it. Still others tried to scale it by standing on the shoulders of men standing on other men’s shoulders.

Witnesses said about 200 people scaled the barrier, but Ben-Ruby said none of the protesters made it into Jerusalem. Most were thwarted by the concrete and barbed wire, and border police made six arrests, he said. No injuries were reported.

The barrier runs along the frontier with the West Bank but snakes inside the territory in several places to include Jewish settlements on the Israel side. Israel says the structure is needed to keep out attackers. The Palestinians condemn it as an Israeli attempt to annex land they claim for a future state.

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

Five of those killed in the airstrikes today were identified as members of the Islamic militant Hamas group, Palestinian security officials said.