Bahrain's most senior Shiite cleric said Friday there is no chance for talks with the Gulf nation's Sunni rulers while security forces maintain their clampdown on protesters calling for equal rights and political freedoms.

The sermon by Sheik Isa Qassim underscored the deep discontent among Bahrain's Shiite majority despite the lifting of martial law-style rules earlier this month and appeals for dialogue by the Sunni monarchy. It also marked another blow to the ruling establishment after organizers of Bahrain's prestigious Formula One race called off efforts to reschedule the 2011 event, which was canceled in March amid the unrest.

"We cannot negotiate in such conditions," Sheik Qassim told worshippers in a mostly Shiite area outside the capital, Manama.

Sheik Qassim, who was joined by other Shiite clerics in a display of solidarity, denounced what he called "daily security harassment" in the form of checkpoints, arrest sweeps and other measures imposed to quell the protests that broke out in February.

He said the pressures were "building hatred among the people."

Shiites represent about 70 percent of the population in the strategic island kingdom, which is home to the U.S. Navy's 5th Fleet. But Shiites have long complained of discrimination at the hands of the ruling Sunni dynasty.

The internal battles also have become a showcase of Arab fears over widening influence by Shiite power Iran.

Sunni Gulf leaders, especially in nearby Saudi Arabia, have strongly rallied behind Bahrain's monarchy, which has accused Iranian-backed Hezbollah in Lebanon and other Shiite groups of aiding the protests.

A 1,500-member Saudi-led military force entered Bahrain in March to help crush the Shiite-led uprising. Martial law-style rules were lifted June 1, but the foreign troops remain and more trials are planned for alleged protest backers.

"The brutal force and abusive language being deployed against us can never destroy our will and desire to achieve our rights and dignity," Sheik Qassim told the crowd.

At least 31 people have been killed since the protests began nearly four months ago, inspired by revolts against autocratic leaders in Tunisia and Egypt.

The U.S. has condemned the violence in Bahrain, but has stopped short of any tangible punishments against the rulers in one of Washington's military hubs in the Gulf.

President Barack Obama met earlier this week with Bahrain's visiting crown prince, Salman bin Hamad Al Khalifa. A White House statement said Obama urged Bahrain to respect the rights to free speech and peaceful assembly, but also reaffirmed America's strong commitment to the kingdom.