A simple, ancient ritual is threatening the delicate security balance atop Jerusalem's most sacred plaza: Jews are praying.

On most days, dozens — sometimes hundreds — of Jewish worshipers ascend to the disputed 36-acre platform that Muslims venerate as Al Aqsa mosque and Jews revere as the Temple Mount with an Israeli police escort to protect them and a Muslim security guard to monitor their movements.

Then, they recite a quick prayer, sometimes quietly to themselves, other times out loud.

Jewish activists call the prayers harmless acts of faith. Police and Muslim officials see them as dangerous provocations, especially given the deep religious sensitivities of the site and its history of violence. Twelve years ago, the presence of Jews on the plaza was so controversial that a brief tour by Israeli politician Ariel Sharon helped trigger a Palestinian uprising that lasted more than four years.

But today Jewish worshipers are commonplace, coming in greater numbers than at any time since Israel's founding and perhaps, some scholars say, as far back as half a millennium ago. Their goal? To challenge the Israeli government's tacit acceptance and enforcement of a ban on Jews praying there by the Islamic trust that has continued to administer the site even after Israel captured the Old City in 1967.

Jewish visits to the plaza are expected to surpass 12,000 this year, up 30% from 2011, according to estimates by Jewish worshiper groups.

"What is provocative about a person wanting to pray?" Rabbi Chaim Richman asked after defying mainstream rabbinical religious rulings and risking arrest by praying on a recent morning near the golden Dome of the Rock. The world's oldest surviving Islamic monument, it's built atop the site where Jews believe their first temple held the Ten Commandments.

"It's the most basic human right," said Richman, international director of the Temple Institute. "I'm not asking to build a temple. I'm just asking to move my lips."

His group and others that advocate the rebuilding of a Jewish temple have often been dismissed by other Israelis and the international community as extremists and zealots who seek to destroy the Dome and the nearby Al Aqsa mosque. Now they are betting this prayer campaign will give their cause more mainstream support, portraying it as a matter of religious equality and free speech.

How can it be, they ask, that in the state of Israel, Jews and Christians are banned from praying at Judaism's holiest site, while Muslims can worship freely? Even the U.S. State Department has cited Israel's ban on non-Muslim prayer on the plaza in its annual report on religious freedom, they note.

The groups want the Israeli government to implement a time-sharing plan that would set aside certain hours for Jewish worship, similar to one used to divide Hebron's Cave of the Patriarchs, a holy site for Muslims and Jews.

Palestinians and Muslim leaders call the prayer campaign the latest ruse designed to instigate clashes so that Israel can justify putting the plaza under military control.

Palestinian Authority President Mahmoud Abbas this month accused Israel of launching a "fierce assault" on the mosque after soldiers broke up a Muslim riot triggered by a group of Jewish worshipers.

Jordan, which has maintained day-to-day supervision of the plaza through an Islamic trust called the Waqf, is asking the U.N.'s cultural body, UNESCO, to condemn Israel for permitting an increase in Jewish prayers.

"The Israeli strategy is to take it over," said Mahdi Abdul Hadi, chairman of the Palestinian Academic Society for the Study of International Affairs, a Jerusalem think tank. "We don't want to share, not because we don't accept them, but because we don't trust them." He said the Hebron agreement was supposed to result in sharing, but it led to bloody clashes between Jews and Muslims, and finally a military takeover.

Hadi also noted that temple-rebuilding extremists set fire to Al Aqsa mosque in 1969 and plotted to bomb the Dome of the Rock in the 1980s.

Jewish prayer at the Jerusalem holy site is certainly not new, but it has been rarely seen during the last 2,000 years. After the Roman destruction of the Second Temple in AD 70, a Jewish presence on the plaza was mostly banned or severely limited during Christian and Islamic rule.

Under the Ottoman Empire, Jews were given access to the Western Wall — believed to be a remnant of the Second Temple compound — but banned from the plaza above, which was reserved for Muslims only, according to Israeli historian F.M. Loewenberg.

Even after Israel took control of East Jerusalem in 1967, most Jews stayed away because of rabbinical prohibitions that warned them against visiting the site lest they inadvertently step on hallowed ground.

In recent years, however, a small but growing number of rabbis have softened that position. At the same time, national religious groups have argued that Israel should exert greater control over what is considered Judaism's holiest site.

In 2000, Jewish visitors were allowed onto the plaza only in groups of two or three at a time and even moving lips in silent prayer might led to arrest, Jewish activists say. Today Jewish groups as large as 150 are allowed to roam the plaza, sometimes drawing nothing more than cold stares and quiet curses from Muslims.

But instead of furtive prayers when police aren't looking, more worshipers are sometimes singing and lying on the ground in keeping with Jewish traditions. Such overt prayer often sparks clashes with Muslims, as occurred this month during the Jewish holiday of Sukkot when a right-wing Israeli politician was arrested for praying.

Police officials say they oppose any attempt to allow non-Muslim prayer on the plaza.

"As soon as that takes place, it causes a response from Israeli Arabs, and the Israeli police have to respond and separate them," said Israeli police spokesman Micky Rosenfeld. "Our aim is to keep the status quo and make sure the different religions can use and respect the site."

Right-wing Israeli lawmaker Arieh Eldad, who recently drafted a bill to impose a time-sharing plan that would allow Jews to pray at specified times, accused Palestinians of using the threat of violence to keep the plaza to themselves.

"Muslims are blackmailing the West, saying they will burn, riot and murder if we practice our right of freedom of speech," he said.

Temple group activists say their strategy is to keep praying and getting arrested, hoping Israeli courts will force the government to drop the ban.

Israel's Supreme Court upheld the right of Jews to pray on the plaza, but gave police broad latitude to restrict access in the name of security. Muslim males younger than 45 are also sometimes banned from the holy site for security reasons.

"We're focusing on prayer for the next year," said Aviad Visuli, a Haifa attorney who represents Jewish activists. "It's something nobody can object to."

Waqf leaders in Jerusalem declined to speak publicly, citing the sensitivity of the issue. But one Waqf official warned that Palestinian and Arab Israeli worshipers are increasingly uneasy over the prospect of sharing the plaza.

"This is a Muslim site," the official said. "If the police don't stop this, the people will. For Muslims, this is a red line."