A British-Ukrainian student living in Kyiv said she woke up to the sounds of explosions on Thursday morning.

Russian President Vladimir Putin announced on Thursday that a military operation had begun in Ukraine, and explosions have been heard in the capital and other major cities.

Valentina Butenko is studying politics at University College London, but returned to Ukraine a few weeks ago to offer help with the security crisis there.

“I woke up this morning to the sound of an explosion,” the 19-year-old, who has a British mother but was raised in Ukraine, told the PA news agency.

“I live on the outskirts of Kyiv so I expect it must have been pretty huge for me to hear it.

“Have been hearing explosions intermittently since 5am … the sky has lit up a few times although it seems to have calmed down slightly now.”

Ms Butenko is in Kyiv with her father, who has asked her to leave for western Ukraine, where he believes it is safer.

However, she said many people are leaving the Ukrainian capital and roads out of the city are “completely blocked with traffic” making it “impossible to get out”.

On how it feels to see the events unfolding in her country, Ms Butenko said: “This morning it was very unexpected… not many people have ever experienced anything like a war zone.

“But the general spirit in Ukraine last few weeks, and me personally, as well, where, you know, we’re very kind of driven to protect our country.

“I’m not overly panicked, I trust our army and that we will protect Ukraine.

“Ukraine is a very hardened country, in terms of dealing with conflict… people here have been mentally preparing for war.”

Ms Butenko urged Western nations to offer a “unilateral” response to the Russian military activity.

“I would really like to see all of the West, the UK especially obviously, present a really strong unilateral response, in whatever ways can be fashioned, whether it’s military support, financial support or incredibly harsh sanctions,” she said.

“It’s really important right now to show the Ukrainian people… this fight for sovereignty and democracy is coming from all sides.”

Daniel Williams is from the Isle of Wight but has been living in Kyiv with his wife and young daughter.

He moved to Lviv in western Ukraine over the weekend and spent Thursday looking for a way to leave the country and reach Poland.

“We moved to Lviv, thank God, over the weekend,” the 45-year-old told PA.

“Lviv is untouched right now other than starting to fill up with people heading west.”