The daughter of the jailed Ukrainian opposition leader Yulia Tymoshenko has said her mother has been "brutally beaten" in prison, as more European governments announced they were boycotting next month's European football championship in protest.

Eugenia Tymoshenko told the Guardian the threat by Germany and other European countries not to send ministers to Euro 2012, co-hosted by Ukraine and Poland, had taken the government in Kiev by surprise. "It's keeping her going," she said of her mother.

On Wednesday Austria said it would be staying away out of solidarity with Tymoshenko. Belgium said it was following suit and that Tymoshenko and other members of her government now in prison should be allowed medical treatment and visits.

Eugenia Tymoshenko said her mother was badly beaten up on the evening of 20 April when prison guards arrived in her cell to transfer her to hospital. Tymoshenko suffers from severe back pain. She is refusing to see doctors provided by Ukraine's ministry of health and instead insists on treatment by German doctors or her own physician.

Three people – the vice-head of the prison colony and two guards – came to the cell late at night and tried to forcibly drag her away, her daughter said. "They started moving towards her and surrounded her bed. They first moved everyone from the building and removed her neighbour. My mother felt these were the last minutes of her life.

"They grabbed a thick woollen blanket from her bed, pulling her off the bed. She managed to stick her hand out and resisted, protecting her life. The vice-head then punched her in the stomach.

"She couldn't breath after the punch. She started screaming, when they were bringing her out of the building. She passed out in the ambulance. She recovered conscious in hospital. She refused everything. She took only painkillers."

Eugenia Tymoshenko. Photograph: David W Cerny/Reuters

She said her mother was now back in prison and "very physically weak". She was now on the 13th day of a hunger strike, her daughter said.

Ukrainian prosecutors claim Tymoshenko's injuries were self-inflicted. Eugenia Tymoshenko claimed her mother's cell was under 24-hour video surveillance, and said the authorities could release tapes proving what had happened.

On Sunday Angela Merkel announced that she and her cabinet would not attend any matches played by Germany in Ukraine unless Tymoshenko was released. Germany's first game, against the Netherlands on 13 June, will be played in Kharkiv, the eastern city where Tymoshenko is incarcerated.

On Tuesday the US secretary of state, Hillary Clinton, called for Tymoshenko to be freed. The president of the European commission, José Manuel Barroso, and the commissioner for justice, Viviane Reding, have said they will not be travelling to Ukraine. The diplomatic fiasco represents an embarrassment for Uefa, European football's governing body.

It is unclear whether David Cameron will follow Germany's lead. The Foreign Office says it is "reviewing the situation". England will play all three of their group stage matches in Ukraine, one in Kiev and two in the eastern city of Donetsk.

Eugenia Tymoshenko declined to give advice to Downing Street but said the EU had to bring "all instruments" to bear on Ukraine's president, Viktor Yanukovych.

"I think European leaders can't stand next to someone who is allowing these kinds of repressions. Standing next to him would look like support," she said. "Yanukovych could have solved this crisis months ago and stopped court proceedings. It's in his power to find a solution."

A Ukrainian court jailed Tymoshenko late last year for seven years following what her supporters and the EU say was a blatantly manipulated show trial.

Berlin has been negotiating for months with Ukraine's government to allow Tymoshenko to be treated in Germany. Her daughter said it would be very difficult for her mother to abandon Ukraine and her life in politics.

She said Yanukovych was probably persecuting her mother out of revenge. She said Yanukovych "felt personally angry and frustrated" after his attempts to rig Ukraine's 2004 presidential election backfired, sparking the pro-western Orange revolution. Yanukovych took power in 2010 after an election regarded internationally as fair, but since then, Eugenia Tymoshenko said, he had embarked on a course of repression and physical violence against his political opponents.

"As Yulia's daughter, as a Ukrainian, I detest what Yanukovych is doing. It's obviously an illegal attempt to keep his main opponents out of the political game." She predicted his government would become more harsh in the runup to parliamentary elections in October.

There has been no comment from Yanukovych's office on the prospect of an EU-wide boycott of Euro 2012, but Ukranian officials have reacted sharply. This week the foreign ministry spokesman, Oleg Voloshin, suggested Germany was "reanimating the methods of the cold war" and said Euro 2012 was about football, not politics. "It's impossible to solve any political issues through boycotting sporting events," he said.