Al-Qaida leader Osama bin Laden has vowed to continue the fight against Israel and not give up an inch of Palestinian land, in an audio recording released Friday.

"We will continue, God permitting, the fight against the Israelis and their allies ... and will not give up a single inch of Palestine as long as there is one true Muslim on earth," the Saudi-born al-Qaida leader said in the tape posted on an Islamist website on Friday.

Bin Laden said Israel's anniversary celebrations were a reminder that it did not exist 60 years ago, and had been established on land seized from Palestinians by force.

"This is evidence that Palestine is our land, and the Israelis are invaders and occupiers who should be fought," he said.

Bin Laden noted that decades of peace initiatives had failed to establish a Palestinian state, and said the West sided with Israel.

"The participation of Western leaders with the Jews in this anniversary celebration confirms that the West backs this Jewish occupation of our land, and that they stand in the Israeli corner against us," he said. "They proved this in practice by sending their forces to southern Lebanon."

He also said Western media had over the years painted Israelis as victims, and the Palestinians who had been displaced from their land as terrorists.

The authenticity of the tape could not immediately be verified but the voice sounded like Bin Laden's.

Laura Mansfield, an organization that monitors Islamist websites, said Bin Laden appeared to be changing his emphasis.

"In his initial messages, Bin Laden's focus was on the removal of U.S. forces from [Saudi Arabia] but in recent years he has more closely wedded himself to the Palestinian issue."

The announcement appeared on various militant message boards on the Internet with a banner announcing Israel's anniversary as the topic, according to Laura Mansfield.

The speech is addressed to "Western peoples" and entitled "The Causes of Conflict on the 60th Anniversary of the State of Israeli Occupation," the SITE Institute monitoring group said. The monitor IntelCenter said the statement was expected to be released within 72 hours.

In a message on March 20, his second in 2008, bin Laden urged Muslims to keep up the struggle against U.S. forces in Iraq as a path toward "liberating Palestine."

Al Qaida has vowed attacks on Jews both within and outside of Israel, and regularly expressed support for the Palestinians.

But despite calls by al Qaeda supporters for the militant network to establish a presence in Palestinian areas, U.S. intelligence officials see no evidence it has done so. It is believed Al Qaida faces competition for turf in the areas from the well-established Hamas.

Al Qaida has vowed attacks on Jews both inside and outside Israel, and regularly expressed support for the Palestinians.

The group is widely blamed for a suicide attack on an Israeli-owned hotel in Kenya and a simultaneous failed attempt to shoot down an Israeli charter jet near Mombasa airport in Kenya in 2002.