In an escalation of the protests that have been going on for weeks, security forces in the Ukraine have stormed a protest, ripping down barricades and tents in the capital Kiev.

Several thousand police in riot gear used their shields to push back protesters and successfully removed some tents and barricades on Wednesday, but as protester numbers grew from hundreds into the thousands overnight, the police were not able to gain total control of the square.

On one of the main streets leading into the square, a large group of protesters in hard hats, appointed to protect the demonstrators, held back a separate unit of riot police.

Priests intoned prayers from a stage on the square and urged police not to use violence.

Al Jazeera's Tim Friend, reporting from Independence Square, said a standoff was in effect.

"The police have effectively reasserted their authority over the square," our correspondent said.

"The protesters are still here. When the riot police first flooded the outskirts of the square the protesters weren't sure how far they would go.

"Protesters moved into a central position where they will remain singing patriotic songs. We have a standoff. It is going to be a long long battle."

The capital has been gripped by more than three weeks of demonstrations against President Viktor Yanukovich's decision to align himself with Russia instead of the European Union.

Protesters sang the Ukrainian national anthem and shouted "Shame!" and "We will stand!" as officers moved in.

Controversial trade deal

The confrontation unfolded as EU foreign policy chief Catherine Ashton and US Assistant Secretary of State Victoria Nuland were in the city to try to talk to the government and the opposition and work out a solution.

Yanukovich's refusal to sign an EU trade deal prompted the country's largest street demonstrations since the 2004 Orange Revolution, which successfully overturned the results of a vote allegedly marred by massive corruption.

Hundreds of thousands of people marched this past weekend, the second in a row that such huge crowds have vented fury at a government they accuse of returning the country to Kremlin control.

Surveys revealed that the pact, which would have deepened the former Soviet republic's economic ties with the 28-nation EU, was supported by nearly half of Ukrainians.

The agreement would make Ukraine more Western-oriented and would be a significant loss of face for Russia, which has either controlled or heavily influenced Ukraine for centuries.

Yanukovich had called on Tuesday for the release of demonstrators arrested in the massive protests and vowed that Ukraine was still interested in integrating with Europe, but stopped far short of opposition demands that his government resign.

Riot police have twice previously dispersed demonstrators with clubs and tear gas, beating some severely enough to send them to intensive care, but there were no immediate signs of such violence early on Wednesday.

Al Jazeera's Robin Forestier-Walker, also reporting from Independence Square, said police appeared to have the "element of surprise" as the government remained in talks to defuse the political standoff.

"Nobody was expecting it," our correspondent said of the police advance.

PHOTO CAPTION

Protesters in Ukrainian capitol Kiev pull down and destroy a statue of Russian communist revolutionary Vladimir Lenin.

Al-Jazeera