Unknown assailants have savagely beaten a dogged Ukrainian journalist who has taken part in pro-EU rallies, triggering outrage among the opposition locked in a confrontation with President Viktor Yanukovych.

Unknown assailants have savagely beaten a dogged Ukrainian journalist who has taken part in pro-EU rallies, triggering outrage among the opposition locked in a confrontation with President Viktor Yanukovych.

Tetyana Chornovil, who writes for the Ukrainska Pravda opposition website, was attacked overnight Tuesday outside the capital Kiev, police said in a statement, citing the journalist.

The prominent journalist, known for her critical reports about Yanukovych and top officials, was driving to Kiev when she noticed she was being followed by a car.

"The driver of the suspicious car began to push her to the side. When she stopped, several men who were following her broke the back window of her car, pulled her out and started beating her," police said in a statement.

"After that she was thrown into a ditch," police said, adding she was found next to her vehicle shortly after midnight.

President Yanukovych condemned the attack and ordered Interior Minister Vitali Zakharchenko to find those responsible.

Later in the day Zakharchenko said three suspects in the beating had been identified and two of them detained.

Police said its "most experienced" investigators were probing the attack on the 34-year-old, who has participated in weeks-long pro-EU protests against Yanukovych.

Chornovil herself said there were "at least two" assailants. "I started running, they began pursuing me," she said in video comments posted on the Ukrainska Pravda website.

"They were hitting me on the head, they were not saying anything, they were just hitting," said the young woman, her face bruised and swollen.

The news site said, citing relatives, that Chornovil was hospitalised with a broken nose, a concussion and multiple bruises.

The attack on the journalist comes after a local pro-EU activist was stabbed in both thighs in the eastern city of Kharkiv on Tuesday evening.

The latest assault caused outrage among opposition leaders, who have been locked in a standoff with Yanukovych over his decision to scrap key political and free trade agreements with the European Union last month.

Several hundred protesters on Wednesday gathered outside the seat of the interior minister, calling for his resignation. Some of the protesters held up pictures of Chornovil.