MOSCOW — Protesters rallying against President Askar A. Akayev burned down police headquarters today in the southern Kyrgyzstan city of Jalal-Abad, raising tensions in a country considered key to U.S. hopes for democracy in Central Asia.

The attack on the police building came in response to predawn action today by special police units who briefly took back control of a regional administration office that had been occupied by demonstrators since early March. A crowd estimated at about 20,000 soon recaptured the governor's office and then marched on the police building, freeing protesters detained there and setting it on fire, witnesses said.

Protesters also briefly took over the airport and used trucks to dump soil and gravel on its runway, in an effort to prevent the government from flying in security reinforcements. The police who drove demonstrators out of the governor's office this morning were believed by protesters to have been flown in from Bishkek, the capital.

Most observers said they did not know about any deaths in the clashes, and presidential spokesman Abdyl Segizbayev said there were none. But the Russian news agency Interfax, in a brief report quoting an anonymous police source, said that up to 10 people may have died.

"The rioters are armed only with sticks. I didn't see any firearms," Chulpan Ergesheva, head of the Jalal-Abad office of the Coalition for Democracy and Civil Society, a human-rights group, said in a telephone interview . "But the people are very edgy, very irritated and angry. ... I am afraid if troops arrive in the city, that may result in big-scale bloodshed."

Akayev, 60, who has been president since 1990, has pledged to step down later this year as required by the constitution. His departure could set an important example for a democratic transfer of power. Akayev is viewed as one of the less authoritarian leaders in a region known for strongman rule. His opponents fear that he plans to remain in power by amending the constitution or holding a referendum to secure another five-year term.

The current crisis was triggered by opposition claims that many of their candidates were cheated of victory in parliamentary elections held Feb. 27 and March 13. The official results gave Akayev overwhelming control of parliament in this poor and mountainous former Soviet state of 5 million people.

The protesters are demanding "the resignation of president Akayev, the annulment of the results of the parliamentary election, the holding of new presidential and parliamentary elections and the freeing of all those who were arrested this morning," Ergesheva said.

Nurvaze Mamatov, a member of the opposition leadership, said in a telephone interview that protesters were still in the city's central square. "We are the only authority existing now in the Jalal-Abad region," he said. "We will wait until someone from the government comes and negotiates our demands with us."

The protesters "don't want to use violence," he said.

"This is a peaceful protest of people who didn't want to put up with the injustice done to them during the election when the real results were stolen from the people," he said.

Both critics and supporters of Akayev see the growing protests as modeled after peaceful uprisings in Georgia two years ago and in Ukraine last year that forced out governments accused of electoral fraud.

In Washington, D.C., the U.S. State Department issued a statement urging talks to achieve a peaceful resolution. "We are concerned by incidents of violence in Jalalabad and other parts of the country," the statement said. "We call on all parties in Kyrgyzstan to engage in dialogue and resolve differences peacefully and according to the rule of law."

Presidential spokesman Segizbayev said that the government "is now looking for ways for its local representatives to hold talks with the leaders of the protesters." The presidential aide stressed that police had been ordered to shoot only into the air and not to fire against the demonstrators.

"These orders were obeyed," he said.

Opposition leader Kurmanbek Bakiyev, a former premier who heads the People's Movement of Kyrgyzstan, said that "what we see now spreading fast across Kyrgyzstan is the people's revolution."

"So far it is peaceful the way it was in Ukraine, and we are doing our best to see it stays that way," he said in a telephone interview from Bishkek. "The police are already taking the people's side. And that is the way it will be everywhere in Kyrgyzstan. There will be no bloodshed."

Times staff writer Sergei L. Loiko contributed to this report.