- Kremlin hawk talks of need for harsh campaign against West - Ex-president Medvedev: Response needed against sanctions - Calls for Western society, infrastructure to be targeted - Western officials have accused Russia of sabotage - Moscow has publicly rejected those allegations

One of Russia's top security officials called on Thursday for Russians to mobilise to inflict "maximum harm" on Western societies and infrastructure as payback for increasingly tough sanctions being imposed on Moscow by the U.S. and its allies.

The statement by Dmitry Medvedev, deputy chairman of Russia's Security Council and Vladimir Putin's predecessor as president, came as the West sharply escalated sanctions on Moscow in efforts to degrade its ability to wage war in Ukraine.

"We need to (respond). Not only the authorities, the state, but all our people in general. After all, they - the U.S. and its crappy allies - have declared a war on us without rules!," Medvedev wrote on his official Telegram channel, which has over 1.3 million followers.

"Every day we should try to do maximum harm to those countries that have imposed these restrictions. Harm their economies, their institutions and their rulers. Harm the well-being of their citizens, their confidence in the future."

Diplomats say Medvedev gives a flavour of hardline and high level thinking in the Kremlin, though Kyiv and Kremlin critics play down his influence, casting him as a scaremonger whose job is to deter Western action over Ukraine.

In his latest comments he spoke of the need to find critical vulnerabilities in Western economies, to target energy, industry, transport, banking and social services, and to stir up social tensions.

Western officials have already spoken about suspected Russian sabotage activities across the West, including arson, with some calling for Russian diplomats' movements to be curbed.

The Kremlin, which said on Thursday it was considering retaliatory action against the U.S. that would best suit Moscow's own interests, and the Russian foreign ministry have rejected the sabotage allegations as false.

'Fake news'

Medvedev, who styled himself as a Western-friendly liberal during his 2008-12 presidency before reinventing himself as one of the Kremlin's toughest hawks, spoke of the need to step up an information war against the West.

"Are they screaming about our use of fake news? Let's turn their lives into a crazy nightmare in which they can't distinguish wild fiction from the realities of the day, infernal evil from the routine of life," he wrote.

Medvedev also called for Russia to weaponise space and arm the West's enemies, as the new U.S. sanctions forced Russia's leading exchange to halt dollar and euro trading, obscuring access to reliable pricing for the Russian currency.