Tens of thousands of South Korean Buddhists rallied Wednesday against alleged religious discrimination by the government of President Lee Myung-bak, the latest setback for his protest-plagued administration.

Discontent among Buddhists has been brewing for months over Lee's alleged favoritism toward Christianity. Buddhists have criticized Lee, a Presbyterian, for filling most of his Cabinet and top presidential posts with other Christians.

Police estimated that 60,000 people, including 7,000 monks clad in gray Buddhist garb, gathered Wednesday in front of Seoul's City Hall.

• Click here to see photos of the march and rally.

"Oppose religious discrimination," the crowd chanted on the grassy plaza as they urged Lee to offer a public apology and fire the head of the national police agency for what they claim is religious discrimination.

They warned they would intensify their protests unless the government takes "sincere steps."

The crowd later marched several blocks to the Jogye Temple, the headquarters of the Jogye Order, South Korea's largest Buddhist sect. Police said there were no clashes.

Lee told his top aides on Monday that his "religious belief and activities should not cause social friction or undermine national unity," the culture ministry said Tuesday.

Lee, however, stopped short of offering an apology and gave no indication he would fire the police chief.

South Korea is a country where religious diversity is widely respected and there is no history of sectarian disputes between Christians and Buddhists.

Buddhism is the oldest major religion in Korea, though Christianity has grown dramatically, especially during the 20th century. According to government figures, Buddhists made up 22.8 percent of the population in 2005, while Christians accounted for 29.2 percent.

Lee is not the first Christian to serve as South Korea's president. Others include Syngman Rhee, Kim Young-sam and Kim Dae-jung.

Of the 15 members of Lee's Cabinet, 12 are Christian and one is Buddhist while the affiliation of two others was not immediately available.

Buddhist anger at Lee's government, which took office in February, intensified in June when the Transportation Ministry dropped Buddhist temples from public transit system electronic maps. The ministry said the omission was a mistake by a lower official and later restored them to the maps.

A photo in which the head of the national police agency posed with a famous pastor at a Christian event also raised Buddhist ire.

Adding fuel to the fire, police inspected the car of the Venerable Jikwan, head of the Jogye Order, in July as he left the Jogye Temple. The temple is harboring some eight civic activists who led weeks of street rallies earlier this year against Lee's decision to resume imports of U.S. beef.

The beef protests rocked the president and Lee's approval ratings plummeted.

Lee "should fire the head of the national police agency to show his sincerity" toward religious neutrality, said Park Jeong-kyu, a spokesman for one of the Buddhist groups that organized Wednesday's rally.

Culture Minister Yu In-chon said Tuesday that the government would make the police chief visit the Buddhist community and express his regret. The police agency had no comment.

Earlier this month, Kang Chang-il, a Buddhist lawmaker and member of the opposition Democratic Party, submitted a bill banning religious discrimination in the execution of public officials' duties.

"The president should have exercised restraint in his personal religious inclination," Ahn Myung-sook, a 51-year-old self-employed woman said at the rally.

Park also called for legislation banning religious discrimination.

In early July, Prime Minister Han Seung-soo, a Catholic, instructed all ministries not to give the mistaken impression that the government favors a specific religion, and he visited the Jogye Temple to express regret over the alleged discrimination, his office said.