Savchenko, who returned from Russia a hero following two years in prison there but was arrested in her home country in March 2018, was freed overnight by a court order after a hearing that began on April 15.

A judge at the Brovary district court outside Kyiv ordered the release of Savchenko and alleged co-conspirator Volodymyr Ruban because the term of their pretrial detention expired at midnight and had not been extended.

Savchenko plans to return to work soon at the Verkhovna Rada, the single-chamber parliament that stripped her of her immunity from prosecution before her arrest, defense lawyer Oleksandr Shadryn said.

But Prosecutor-General Yuriy Lutsenko said that the accusations against Savchenko and Ruban remain in place. He said her release suggests that Ukraine's court system is "gravely ill."

Another lawyer for Savchenko, Dmytro Loyfman, also said that her release from pretrial detention would not affect the conduct of the case against her. The Unian news agency reported that the next hearing in the case is scheduled for May 7.

The abrupt release came five days before the presidential runoff between incumbent President Petro Poroshenko and comedian Volodymy Zelenskiy.

It was the latest twist in a dramatic series of events for Savchenko, who for a time was a hero of the war that has killed some 13,000 people in the eastern region known as the Donbas since Russia fomented unrest and backed separatists after pro-European protests drove Moscow-friendly President Viktor Yanukovych from power in 2014.

Savchenko says she was abducted in the combat zone later that year and taken to Russia. She spent two years in prison there, defying the Kremlin with a series of hunger strikes, and returned to a hero's welcome in Kyiv when she was released as part of a prisoner swap in May 2016.

Elected to the Rada while still in Russian captivity, she had declared her intention to run in this year's presidential election. But she was stripped of her parliamentary immunity on March 22, 2018, a week after Lutsenko accused her of plotting to destroy the Rada’s roof cupola with mortar shells, kill surviving lawmakers with assault-rifle fire, and overthrow the government.

Savchenko has maintained her innocence. She said in March 2018 that undercover agents attempting to discredit her encouraged her to plan to overthrow the government, and that she pretended to go along with the conspiracy in a bid to embarrass the authorities and expose what she said was their duplicity.

Before her arrest Savchenko had drawn fire from several political camps, facing criticism for holding talks with the separatists without government consent and for comments nationalists said indicated she advocated accepting Moscow's seizure of the Crimean Peninsula from Ukraine.

Ruban was detained in March 2018 while crossing into government-controlled territory in eastern Ukraine, allegedly with large amounts of weapons and ammunition hidden in a shipment of furniture.

Courts had extended pretrial detention periods for both Ruban and Savchenko at the request of prosecutors several times before their release.

_{With reporting by the Kyiv Post, Unian, nv.ua, and TASS}