KIEV, Ukraine (AP) — Ukraine's top security agency says that protesters have seized over 1,500 firearms, and is announcing a nationwide "anti-terrorist" operation to restore order.

In a statement Wednesday, Ukraine's Security Service said that such actions by "radical and extremist groups" threaten the lives of millions of Ukrainians.

Meanwhile, the European Union could impose sanctions on Ukraine, where the latest clashes between police and protesters have left at least 25 people dead and hundreds injured.

President Viktor Yanukovych says opposition leaders "crossed a line when they called people to arms."

The head of the European Commission, Jose Manuel Barroso, accuses the Ukraine government of using excessive force, and EU foreign ministers will hold an emergency meeting tomorrow.

IOC President Thomas Bach has expressed his condolences to victims of the violence in Ukraine and praised Ukraine's Olympic athletes for continuing to compete at the Sochi Games.

Bach says the IOC's "thoughts and sympathy are with the Ukrainian team at what must be very difficult time."

Ukraine sent a team of 43 athletes to Sochi.

Bach says "the way they have continued to represent their nation with great dignity is a credit to them and their country."

He says "their presence here is a symbol that sport can build bridges and help to bring people from different backgrounds together in peace."

Earlier, the IOC rejected a request for Ukrainian athletes to wear black armbands to honor those who died.

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