US Secretary of State Mike Pompeo has been subpoenaed.
A Democratic-led US House of Representatives committee issued the order on Friday.
They want to him to hand over documents regarding contact the US government had with the Ukrainian government.
Earlier this week House Speaker Nancy Pelosi launched a congressional impeachment inquiry of US President Donald Trump.
Tennessee death row inmate Christa Pike survives lethal execution attempt
Christa Pike, convicted of murdering a schoolmate three decades ago, survived Tennessee's effort to execute her by means of lethal injection late on Wednesday, prison officials said, foiling the state's first attempt to put a woman to death in two centuries.
Injuries and arrests as French high school student protests spread
Dozens of people have been injured and hundreds arrested, most of them teenagers, officials said, in a wave of French student protests against teacher shortages and dilapidated buildings that on Wednesday spread to more schools across the country.
Russia hits power plants, kills four, leaves Kyiv under smoke
Russian drone and missile attacks on Kyiv and nearby areas killed four people, damaged energy infrastructure and shrouded the capital in smoke, Ukrainian officials said on Wednesday.
US forces exit remaining bases in Iraq
US forces have withdrawn from their remaining bases in Iraq on Wednesday, raising fears they will leave behind a security vacuum.
Shark stranded in South Korean canal draws 600,000 visitors as rescue bid fails
A shark stranded in a canal in the South Korean port of Busan has become the country's latest wildlife sensation, with the city saying about 600,000 people have flocked to see it over the past two weeks.
