Boris Johnson has hinted that Germany may be concerned about the imposition of sanctions against Russia because of its dependence on Russian gas and told MPs diplomatic efforts are being made to persuade Berlin and others to go further. The British prime minister said that “European friends” had concerns about imposing the toughest possible sanctions on Russia if it invades Ukraine because of their “heavy dependence” on Russian gas – and also declared the UK would be willing to deploy more troops to eastern Europe if Ukraine was attacked. Johnson was giving a statement to MPs a day after an evening call between western leaders including the US president, Joe Biden, the German chancellor, Olaf Scholz, and the French president, Emmanuel Macron. “I think the house needs to understand that one of the big issues that we all face in dealing with Ukraine, in dealing with Russia, is the heavy dependence of our European friends in particular on Russian gas,” Johnson said. “It was clear in the conversations last night that, in this era of high gas prices, we are bumping up against that reality. So the job of our diplomacy now is to persuade and encourage our friends to go as far as they can to sort this out and to come up with a tough package of economic sanctions because that is what this situation requires,” the prime minister added. Johnson was responding to a question from the SNP’s Commons leader, Ian Blackford. The prime minister had initially said that western allies were still talking about cutting off Russia from the Swift banking global payments system in the event of an invasion. “I’m afraid it can only really be deployed with the assistance of the United States, though. We’re in discussions about that,” he added. However, over the weekend Germany’s foreign minister, Annalena Baerbock, had expressed doubts about the idea. The Labour leader, Keir Starmer, said Russia should be hit with “widespread and hard-hitting sanctions” that he said must include cutting its access to the international financial system. He also called on Johnson to prevent Britain being used to launder Russian money: “If we take our obligations to global security seriously we cannot go on allowing ourselves to be the world’s laundromat for illicit finance.” Other participants on the evening video call were the leaders of Italy, Poland, the EU and Nato. Germany relies on Russia for about a third of its gas supplies, while Johnson said the UK imported about 3%. The plan, Johnson said, was to impose “coordinated and severe economic sanctions heavier than anything we have done before against Russia” – and that efforts were going on in “finalising these measures as swiftly as possible in order to maximise their deterrent effect”. Sanctions would target prominent individuals and Russian companies, Johnson added in a later answer to Conservative MP Tom Tugendhat. Britain would also be willing to deploy more troops to eastern Europe if Russia were to invade. “We would look to contribute to any new Nato deployments,” the prime minister said. On Monday, the US said it would put 8,500 troops on high alert to deploy to Europe if necessary, while France said it was willing to send forces to Romania. In response, Russia said it was watching with great concern. The Kremlin spokesperson, Dmitry Peskov, accused Washington of fuelling tensions over Ukraine – repeating Moscow’s line that the crisis is being driven by US and Nato actions rather than by its own buildup of an estimated 100,000-plus troops near the Ukrainian border. Earlier, Britain had warned that Russian elements were already laying the ground for an attack in Ukraine. James Heappey, a defence minister, writing in the Sun, said: “As I write, we are becoming aware of a significant number of individuals that are assessed to be associated with Russian military advance-force operations and currently located in Ukraine.” UK defence sources said the warning was based on intelligence, and was in addition to a warning made by the foreign secretary, Liz Truss, on Saturday of a Kremlin plot to install a pro-Moscow government in Ukraine. Advance-force operations is a US military term and covers any activity, from reconnaissance and surveillance to information warfare, aimed at softening a local population ahead of a potential attack.