Russian President Vladimir Putin said on Tuesday that he had the right to use "all means" to protect his citizens in Ukraine, denying he had sent troops to Crimea.

Russian President Vladimir Putin said on Tuesday that he had the right to use "all means" to protect his citizens in Ukraine, denying he had sent troops to Crimea.

The Kremlin chief described the ouster of Kremlin-backed president Viktor Yanukovych after protests in Kiev which left nearly 100 people dead last month as an "armed seizure of power".

"We reserve the right to use all means to protect, but there is currently "no need" to send troops into Ukraine," Putin told reporters at his Moscow residence in a briefing broadcast live on state television.

"There can only be one assessment of what happened in Kiev and Ukraine as a whole -- this was an anti-constitutional takeover and armed seizure of power," he added.

Pro-Moscow forces remain in de-facto control of Crimea -- a strategic Black Sea peninsula that has housed the Russian Black Sea Fleet since the 18th century.

At his press conference, Putin also denied that Russian forces took part in operations in autonomous Crimea.

"No, they did not participate," he said. "There are lots of uniforms that look similar."

Washington announced a raft of tough sanctions against Russia Monday, suspending post-Cold War cooperation such as joint exercises, bilateral meetings, port visits and planning conferences.