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.
Landslide at Guinea landfill kills 30, government says
A landslide at a landfill in Guinea's capital has killed 30 people, the government said on Sunday, after heavy rains overnight prompted the collapse of a massive mound of waste that engulfed nearby tents and shacks.
Ukraine wants peace but won't give in, Zelenskyy says on Independence Day
Ukraine wants peace but will not just give in to Russia at any price, President Volodymyr Zelenskyy said on Monday in a defiant speech marking Independence Day celebrations.
New Zealand to introduce bill banning social media for children under 16
New Zealand's coalition government will introduce a bill in parliament on Monday that seeks to ban children under 16 from using social media, and proposes fines of up to 10 per cent of a platform's global revenue for non-compliance.
Ukrainian drone attack kills three in Russia's Krasnodar, officials say
Three teenagers were killed and another eight people, including seven children, were wounded after drone debris hit a private childcare centre in southern Russia's Krasnodar region overnight, Russian officials said.
Coach carrying German high-school students crashes in Netherlands
A coach carrying high-school students from Germany crashed in the east of the Netherlands early on Monday, injuring eight people, who were taken to hospital, Dutch police said.
