Britain's government said Friday it could seize an exclusive London flat bought for cash by a woman connected to Russian Foreign Minister Sergei Lavrov, under a new sanctions regime coming into force next week.

The Economic Crime Bill – which is being accelerated into law after Russia invaded Ukraine – will lower the bar for the government to slap "unexplained wealth orders" on people with no discernible valid income.

The government said those could include Polina Kovaleva, 26, the daughter of Svetlana Polyakova, who is reportedly Lavrov's long-time mistress.

Along with Russian President Vladimir Putin, Lavrov has been personally sanctioned by Britain.

Opposition Labour Member of Parliament Chris Bryant has said Kovaleva and Polyakova should be added to the list.

The U.K.'s land registry database lists Kovaleva as the owner of a 4.4 million pounds ($5.75 million) apartment in the plush London area of Kensington, bought mortgage-free in 2016.

The flat lies not far from the London mansion of Chelsea Football Club owner Roman Abramovich, whose U.K. assets have been frozen over his ties to Putin.

Maria Pevchikh, an investigator for jailed dissident Alexei Navalny's anti-corruption foundation, said Kovaleva's "only source of money is her unemployed mother who happens to be Lavrov's informal wife."

"This is the textbook example of unexplained wealth. The property can be legally seized right now," Pevchikh tweeted.

Speaking to LBC radio, technology minister Chris Philp said the new bill would strengthen government investigators' ability to impose orders demanding that asset owners explain the source of their money.

"So people who show up in London, a bit like the case you mentioned – buying a £4 million property with apparently no legitimate means to do so – those unexplained wealth orders are designed to get behind that."

Then, Philp said, the government could "potentially confiscate assets that have been acquired like expensive property, where there's no good explanation for where that money came from."

Philp also defended the pace of the government's action Thursday against Abramovich, after Labour and some lawmakers from the ruling Conservative party had demanded much earlier sanctions against the Chelsea owner.

"These Russian oligarchs have very expensive lawyers. They're highly litigious," the minister said.

"It was very important to make sure this was done in a way that was totally legally watertight and legally defensible."