* Bubka says "shocked" by deaths
* 25 protesters, police killed (Updates with more Bubka quotes, details)
By Karolos Grohmann
SOCHI, Russia, Feb 19 (Reuters) - Ukrainian Olympic Committee chief and former pole vault champion Sergey Bubka on Wednesday called for an end to violence in his country as Ukraine's athletes struggled to focus on competing at the Sochi Winter Games.
"I'm shocked by what is happening in my native country," said Bubka, who is also an adviser to the president of Ukraine and an Executive Board member of the International Olympic Committee. "Deep condolences to all victims in Ukraine.
"I am once again urging all parties to stop the violence. There is no 'their' Ukraine, or 'your' Ukraine. It is OUR Ukraine," he wrote in a statement.
At least 26 people were killed in anti-government protests, and on Wednesday President Viktor Yanukovich accused pro-European opposition leaders of trying to seize power by force.
Bubka added: "For the sake of the future of our kids let's do everything possible to get back to negotiations and make a compromise."
"I'm ready to do everything I can to help the peaceful process because I love my country and our people and believe in our future, together."
The unrest has spread to at least three cities in the western part of the country. Police said protesters had seized regional administration headquarters in the cities of Ivano-Frankivsk and Lviv, which is bidding for the 2022 winter Olympics.
Media said protesters torched the main police station in the city of Ternopil.
"I think they should stop it for the Olympics ... Now in Ukraine they're going mad," said Dmytro Mytsak, a Ukrainian giant slalom skier from Kiev.
Ukraine's athletes asked on Wednesday whether they could compete wearing black armbands, but the request was denied by the International Olympic Committee.
The 18-year-old Mytsak said his parents had not mentioned the violence when they spoke before the race on Wednesday, but he was already aware of the deaths.
"We're trying not to talk about this and not to think about it for the time being. Of course it's sad what's happened," he told Reuters
"Yes it's a distraction, everyone's talking about it - even just now at the start, at the finish, people are saying, 'what's happened in your country, what's happened?'
"We're getting support from the Russian spectators and I'm grateful for that."
Many people have been killed by gunshot and hundreds have been injured, with dozens in a serious condition, police and opposition representatives said.
"Those are terrible scenes," IOC spokesman Mark Adams told reporters. "I'm sure that the Olympic truce is an important, symbolic thing for us - I'm not sure really that it plays much part in what's gong on there.
"But clearly we hope that the situation will be solved as quickly and with as less bloodshed as possible," Adams said.
He added that any talk of the Lviv bid, for which Bubka is a leading figure, was secondary at the moment.
"In terms of Lviv and the bid, I think at this stage with the terrible things that are going on at the moment, I think we should concentrate on what's going on there and hope that solves itself in as peaceful a way as possible.
"It is not really right to be speculating on an Olympic bid when such things are happening."
Lviv is up against Poland's Krakow, Beijing, Kazakhstan's Almaty and Norwegian capital Oslo with a shortlist of cities to be drawn up in five months. (Additional reporting by Mark Trevelyan in Rosa Khutor; Editing by Mike Collett-White/Peter Rutherford)