BBC: The UK government has said it will sanction Russia over President Vladimir Putin’s decision to recognise two breakaway regions in eastern Ukraine.
Recent legislation will be used to impose restrictions on people and organisations linked to Russia, the BBC understands.
Government sources say sanctions would be “ratcheted up” in the event of a Russian incursion of Ukraine.
The foreign secretary said Russia’s actions would not go “unpunished”.
In a tweet, Liz Truss she confirmed sanctions would be announced on Tuesday “in response to their breach of international law and attack on Ukraine’s sovereignty and territorial integrity”.
Several of the UK’s western allies, the US, France and the European Union, made similar statements, condemning Mr Putin’s move and promising sanctions.
Prime Minister Boris Johnson will chair a Cobra emergency response meeting at 06:30 GMT on Tuesday.
A No 10 spokesman said the meeting would discuss the latest developments in Ukraine and co-ordinate the UK response, including agreeing a “significant package of sanctions to be introduced immediately”.
Hours earlier, Mr Putin signed a decree recognising the independence of the self-declared people’s republics of Donetsk and Luhansk in eastern Ukraine.
Russian-backed rebels have been fighting Ukrainian forces in those regions since 2014 in a conflict that has claimed the lives of more than 14,000 people.
Mr Putin’s decision has been preceded by weeks of tensions and intense diplomacy over a build-up of Russian troops on Ukraine’s borders.
Now western countries fear those military forces could cross Ukraine’s borders to occupy the rebel regions recognised by Mr Putin.
The decree signed by Mr Putin says Russian armed forces will perform “peacekeeping functions” in Donetsk and Lugansk.
In a lengthy TV address, Mr Putin, appearing visibly angry at points, claimed “modern Ukraine was entirely created by Russia” and were part of its ancient lands.
But in recent weeks, Russia has repeatedly denied it has plans to invade Ukraine and accused the West of “hysteria”.
Mr Putin delivered the speech as UK Prime Minister Boris Johnson was giving one of his own in Downing Street on measures to lift Covid-19 restrictions.
Mr Johnson said Mr Putin’s decision to recognise the two separatist Ukrainian regions was “plainly in breach of international law” and a “flagrant violation of the sovereignty and integrity” of the country.
Mr Johnson said the decision was a “very ill omen” that things were moving in the wrong direction in Ukraine.
“The UK will continue to do everything we can to stand by the people of Ukraine with a very robust package of sanctions,” he said.
He said it was becoming clear there was a need to “start applying as much pressure as we possibly can” because it was hard to see how the situation would improve.
Mr Johnson finished his news conference by saying he would talk to Ukrainian President Volodymyr Zelensky to offer him the UK’s support.
Earlier this month, the UK government passed new legislation that expanded its powers to impose sanctions on those directly linked to Russian actions in Ukraine.
The legislation gave the government powers to impose sanctions on Russian businesses and individuals in strategically significant sectors, such as the chemical, defence, extractives, ICT and financial services industries.
