U.S.-allied President Mikhail Saakashvili declared a state of emergency Wednesday in the capital of Georgia, where six days of demonstrations have fueled a worsening crisis.

Saakashvili has blamed Russia for fomenting the unrest in the former Soviet nation. His prime minister, Zurab Nogaideli, said in a televised statement that there had been an effort to overthrow the pro-Western government.

"An attempt to conduct a coup was made, and we had to react to that," Nogaideli said.

The emergency declaration "will temporarily ban demonstrations and protests, and calls in the media for violence, and the ouster of the government by force," Nogaideli said.

He said that the presidential decree would be submitted to parliament for approval within the next two days as required by the constitution.

Riot police earlier used tear gas and water cannons to break up demonstrations, before bursting into the offices of a pro-opposition television station that went off the air moments later.

Georgia's Imedi television station describes itself as independent but is seen as a key opposition mouthpiece by authorities. It has carried statements by opposition leaders and broadcast footage of police breaking up protests Wednesday. More than 100 people were hospitalized after police drove opposition demonstrators from two protests in the capital, Tbilisi. Police used truncheons on some protesters and rubber bullets at one demonstration.

"Riot police are here, something horrible is going on," the Imedi announcer said before the station went off the air.

The Interior Ministry said it would put out a statement on the situation at Imedi later in the day.

"Journalists aren't in danger, they will be allowed to go home," ministry spokesman Shota Utiashvili told The Associated Press.

Salome Zurabishvili, a former foreign minister who is now an opposition leader, said she was inside Imedi's headquarters when more than 100 police broke into the building and took control.

The demonstrations in Tbilisi have created the gravest challenge for Saakashvili since he was propelled to power in the 2003 Rose Revolution mass protests.

Saakashvili said in a televised address that Russian spy agencies were behind the protests and that three Russian diplomats were being expelled because of espionage activities.

Russia's Foreign Ministry dismissed Saakashvili's claims as an "irresponsible provocation" and said they were an attempt to distract attention from domestic problems.

Zurabishvili said that the shutdown of Imedi means that Georgia no longer has independent television because Rustavi 2 television, which is technically independent, has toed the official line.

Imedi was founded by Badri Patarkatsishvili, a prominent businessman who authorities claim is behind the protests against President Mikhail Saakashvili. Patarkatsishvili earned his fortune in Russia during the turbulent 1990s, but he returned to his native Georgia in 2000.

Patarkatsishvili recently handed over his controlling stake in Imedi to Rupert Murdoch's News Corp., saying he wants to focus on supporting opposition parties.

The main demonstration Wednesday was in a street outside Parliament, where Saakashvili opponents have gathered since Friday, first to demand changes in election schedules and legislation and then to demand his resignation.

As police advanced, protesters retreated down Tbilisi's main avenue. Police fired tear gas from the beds of pickup trucks. Many wore gas masks, and live television broadcasts showed several people choking, including police. Scattered fist fights broke out between uniformed police and protesters.

Later, riot police again used tear gas, water cannons and rubber bullets to break up another demonstration in downtown Tbilisi. Some police used truncheons to beat protesters who clambered over the city's walls, threw stones and taunted police.

About 360 people sought medical assistance, and more than 100 of them have remained hospitalized, Health Ministry spokeswoman Nino Kochorashvili told The Associated Press.

Saakashvili said he regretted the use of force, but argued that it was necessary to prevent the country from sliding into chaos.