BEIJING (AP) – Police descended on a group of foreign pro-Tibet activists and some disgruntled business owners from Hong Kong on Thursday, taking both groups away minutes after they displayed protest signs in central Beijing.

The abrupt end of the separate protests — and the sentencing of six foreigners to 10 days of detention for “disrupting public order” — underscored China’s determination to prevent any disruption during the Olympics.

The government has said it would allow protests in three areas during the games, but no application to hold a demonstration has been accepted. One of the Hong Kong protesters on Thursday, Wang Pei, told the Associated Press his group also tried to submit an application.

“But police put up many obstacles to make it difficult,” Mr. Wang said from a police station where the group — five men, two women and a teenage girl — was being held.

The group went to the Zhongnanhai compound in central Beijing where China’s leaders live and work and waved a green and yellow sign that said “Hong Kong businesses want justice.” After about five minutes they were taken away by police.

Mr. Wang said he and several others in the group had invested in a business in Shanghai but were cheated out of their money and had not been able to reclaim it despite winning a court ruling that awarded them $150,000 in a settlement.

Police released a brief statement late Thursday saying that six foreigners arrested Tuesday were sentenced to 10 days of detention for “disrupting public order.” One was identified only as “Thomas,” and officials gave no further details about the foreigners’ identities, nationalities or activities.

Earlier, police seized four activists protesting Chinese rule in Tibet as they unfurled a Tibetan flag and shouted “Free Tibet” south of the National Stadium, the New York-based Students for a Free Tibet said.

The group put the number of police at 50. A spokeswoman for the Beijing Public Security Bureau declined comment, and the whereabouts of the activists was not known.

“The fact that there were so many undercover police following them just made them go with the action urgently,” said Kate Woznow, the group’s campaign director.

Two Associated Press photographers were roughed up by plainclothes security officers, forced into cars and taken to a nearby building where they were questioned before being released. Memory cards from their cameras were confiscated.

In Washington, State Department spokesman Robert Wood said American officials were looking into the reports of arrests.

Generally, he said, “We are concerned about any actions taken by the Chinese that limit freedom of speech, freedom of movement.”

Some 77 applications were lodged to hold protests, none went ahead. Rights groups say the zones were just a way for the Chinese government to put on an appearance of complying with international standards. A handful who sought a permit to demonstrate was taken away by security officials, rights groups said.

Earlier this week, two elderly Chinese women — Wu Dianyuan, 79, and her neighbor Wang Xiuying, 77 — who applied to protest were told they would be sent to a labor camp for a year. They were still at home Thursday under the surveillance of a government-sanctioned neighborhood watch group, Wang’s son Li Xuehui said.

Mr. Li said no cause was given for the order to imprison the pair. Activists said the order was an intimidation tactic.