Russian forces enter Kharkiv as Ukrainian oil and gas facilities burn

Russian troops were seen on the streets of Ukraine's northeastern city of Kharkiv on Sunday as airfields and fuel facilities suffered huge attacks in what appeared to be the next phase of an invasion.

The US and Europe have responded by providing weapons to Ukraine and are preparing new powerful sanctions to further isolate Moscow.

Russian troops have blown up a natural gas pipeline in the Ukrainian city of Kharkiv, Ukraine's state service of special communications and information protection said.

A mushroom-shaped explosion was shown in a video it posted on the Telegram messaging app.

It was not immediately clear how important the pipeline was and whether the blast could disrupt gas shipments outside the city or the country. Despite the war, Ukraine continues to ship Russian natural gas to Europe.