A Kyiv court has placed former Ukrainian prime minister Yulia Tymoshenko under arrest for violating court procedures during her abuse-of-office trial.

Acting on Judge Rodion Kireyev's orders, police arrested Ms. Tymoshenko Friday after the judge agreed with a prosecution motion for her arrest.

During her trial, Ms. Tymoshenko has refused, as required, to stand up while addressing the judge, repeatedly insulted him and questioned his objectivity. Judge Kireyev denied a prosecution motion last month to arrest Ms. Tymoshenko for similar behavior.

The 50-year-old Ms. Tymoshenko is charged with abusing her powers by overstepping her authority as prime minister to sign a natural gas deal with Russia in 2009. Prosecutors say it was a bad deal for Ukraine. Ms. Tymoshenko has denied the charges.

Before her courtroom arrest, Ukrainian Prime Minister Mykola Azarov and Energy Minister Yuriy Boiko made surprise appearances as witnesses for the prosecution.

Ms. Tymoshenko, the country's top opposition leader, has denounced the trial as an attempt by President Viktor Yanukovych to bar her from elections. She narrowly lost to Mr. Yanukovych in presidential elections last year.

The United States has criticized the Tymoshenko trial and other corruption probes involving her and her top allies as having “the appearance of politically motivated prosecutions.”

If convicted, she would be barred from running in upcoming parliamentary and presidential elections.

Ms. Tymoshenko became an international figure in 2004 as a leader of Ukraine's “Orange Revolution,” a series of street demonstrations that effectively ended Mr. Yanukovych's first bid for the presidency.