Details remain unclear about a series of reported shooting incidents that rocked the capital Tashkent late on August 29 evening.
At least two people were killed in the shootings, although human rights activists speaking to RFE/RL's Uzbek Service say the number could be as high as six.
In addition, at least three law enforcement officers were wounded in the shoot-out, which took place near the Kukcha Mosque and the First Hospital in Tashkent's old city.
Uzbek security has been increased to 'unprecedented' levels.
Local witnesses said police cordoned off the area as they began firing at two men who tried to hide in a two-story building. Special police forces were also seen at the scene.
According to witnesses, the shoot-out lasted for about 20 minutes.
Several armored personnel carriers rushed to the area, followed by ambulances.
One or both of the confirmed fatalities are believed to be police officers. However, witness reports suggest passersby may also have killed in the shooting.
Surat Ikromov, a Tashkent-based human rights activist, said he arrived in the Kukcha area an hour after the shooting and eyewitnesses told him that "two women were killed there. Other sources say several policemen were injured and were taken to nearby First Hospital. So far, government agencies are not giving any information."
The regional news website ferghana.ru quoted witnesses as saying several other shoot-outs took place the same night in different areas of Tashkent, including the neighborhood of Algoritm, the Farhad bazaar, and three streets in the Chilanzar district.
Uzbek authorities have not officially commented on the incidents, but at least one Uzbek website quoted Interior Ministry officials as saying the shoot-out in Kukcha was a police raid against "high-profile" criminals.'Unprecedented' Clampdown
The deadly incidents come amid tightened security ahead of nationwide preparations for celebrations on September 1 of Uzbek Independence Day and Tashkent's 2,200th anniversary.
Independence Day celebrations usually last for a few days, and the government is often seen as using the event as an opportunity to trumpet its accomplishments.
The celebrations will include an annual presidential address to the nation, the presidential pardon of prisoners, as well as numerous formal gatherings, concerts, and other festivities.
Uzbek media have reported that "unprecedented security measures" have been put in place in Tashkent to prevent any possible security threats during the Independence Day events.
Nearly 50 people were killed in a series of bombings in March and April 2004.
The authorities have temporarily closed the border with Kyrgyzstan to prevent extremists and other armed groups entering the country from its neighbor.
Last May, an unknown armed group attacked the Khanabad border post. The attack was followed by several explosions in the eastern Uzbek city of Andijon, the site of a massive government crackdown on protesters in 2005.
Uzbek authorities blamed this year's Andijon explosions on suicide bombers. Heading into the several days of celebrations, officials are eager to prevent a fresh wave of violence. Extremists Blamed
Tashkent has seen a number of deadly attacks in the past decade.
Multiple bombings in February 1999 targeting government buildings in the Uzbek capital left 16 people dead and over 120 injured.
In March and April 2004, a series of suicide attacks were launched in Tashkent and Bukhara, apparently targeting the police. The violence killed nearly 50 people, including militants, police officers, and civilians.
In July 2004, deadly suicide bombings targeted the U.S. and Israeli embassies.
The Uzbek government accuses religious extremists, including the Islamic Movement of Uzbekistan, Hizb ut-Tahrir, and the Islamic Jihad Union, of masterminding the attacks.
Some of the groups have claimed responsibility for some of the attacks.RFE/RL's Uzbek Service contributed to this report