Russia hit back Wednesday at US threats of direct sanctions against President Vladimir Putin, saying moves against the Russian leader would be ineffective and hurt efforts to lower tensions over Ukraine.

Officials from France, Germany, Russia and Ukraine were set for talks in Paris on Wednesday in the latest bid to ease a crisis sparked by fears that Moscow is preparing an invasion of its pro-Western neighbor.

The West has warned Russia of severe consequences if it does invade, and on Tuesday, Washington said there could be sanctions personally targeting Putin.

Reacting to the news, Kremlin spokesman Dmitry Peskov dismissed the threats as worthless because senior Russian officials are barred from holding assets abroad.

But such a move, he said, would do serious damage to diplomatic efforts to ease ratcheting tensions over Ukraine.

"Politically, it's not painful, it's destructive," Peskov told reporters.

The Kremlin has previously said any US sanctions personally targeting Putin would be akin to crossing a red line, warning the move could result in a rupture of bilateral ties.

US President Joe Biden said Tuesday that any Russian military attack on Ukraine would trigger "enormous consequences" and could even "change the world".

High-tech export sanctions

Echoing Biden's message, a senior US official described potential economic sanctions "with massive consequences" that would go far beyond measures implemented in 2014 after Russia annexed Ukraine's Crimea region.

The official said new measures would include restrictions on exports of high-tech US equipment in the artificial intelligence, quantum computing and aerospace sectors.

Cutting Russia off from these technologies would hit Putin's "strategic ambitions to industrialise his economy quite hard", the official said.

The speaker of Russia's lower house said Wednesday that Washington's threat against Putin showed the US "wants a loyal Russian president that it can control".

"The United States is not happy that under President Vladimir Putin, the Russian Federation has become strong and independent," Vyacheslav Volodin wrote on social media.

During weeks of talks between Russian, US and European diplomats, Western leaders have repeatedly warned of far-reaching economic measures against Moscow in the event of an attack.

The next round of talks in Paris on Wednesday will bring together one of Russia's deputy prime ministers and a senior aide to Ukrainian President Volodymyr Zelensky, as well as diplomatic advisors to French President Emmanuel Macron and German leader Olaf Scholz.

Negotiations so far have failed to ease tensions, though Washington and Moscow have agreed to keep talking.

Russia to take 'necessary measures'

Russia is expecting this week to receive written US responses to sweeping security demands Moscow made last year that seek to dramatically limit NATO's reach and capabilities in Eastern Europe and the ex-USSR.

Russia Foreign Minister Sergei Lavrov warned in an address to lawmakers Wednesday that Moscow would take "all necessary measures" if it didn't receive constructive responses and if the West continued its "aggressive policy".

Moscow has meanwhile announced a spate of military drills including in Belarus, and said Tuesday it would hold fresh exercises involving 6,000 troops near Ukraine and within the Crimea region.

As part of separate naval exercises announced this month, Russia warships entered the Barents Sea on Wednesday, the North Fleet said in a statement.

The West has accused Russia of massing some 100,000 troops along the Ukrainian border.

Ukrainian Foreign Minister Dmytro Kuleba said Wednesday that the number of Russian troops "is insufficient for a full-scale offensive" but does pose "a direct threat" to Ukraine.

Fears of a Russian invasion follow on from Moscow's annexation of the Crimean peninsula in 2014 and the capture by pro-Kremlin separatists of two self-proclaimed breakaway republics in Ukraine's east.

More than 13,000 people have died in the fighting between government forces and the pro-Russian rebels.