Ukraine on Thursday thanked Britain’s Boris Johnson for supporting the war-affected nation during “the hardest times” following Russia’s invasion, after the politician stepped down as Conservative leader, clearing the way for his departure as prime minister.

Also read: What happens after a British Prime Minister resigns from the post?

“Thanks @BorisJohnson for… always being at the forefront of supporting Ukraine,” presidential aide Mykhaylo Podolyak wrote on Twitter.

On Thursday, British Prime Minister Boris Johnson resigned after the defections plunged the Conservative Party-led government into a deeper political crisis. The decision to step down comes after one of his closest allies, Treasury Chief Nadhim Zahawi, told the prime minister to resign for the good of the country.

Also read: Boris Johnson resignation: What’s next for UK economy

With the scandal-ridden leader resigning, the race to replace Johnson could take weeks. That would leave the world’s fifth-biggest economy at risk of further drift at a time when sterling is near two-year lows against the dollar and the Bank of England is in a dilemma about raising interest rates without damaging economic activity.

Also read: Boris Johnson resigns as British Prime Minister

The duration of Conservative Party leadership contests varies. Theresa May needed less than three weeks to win after David Cameron quit in 2016 as other contenders dropped out.

Also read: Five issues that led to the resignation of UK Prime Minister Boris Johnson

In April this year, Johnson met Ukrainian President Volodymyr Zelensky in Kyiv and pledged a new package of military and economic support. The move helped bolster Johnson and his supporters, who argue the government should not focus on domestic political squabbles.