MOSCOW - Russian President Vladimir Putin on Monday announced a three-day truce starting from midnight of May 8 (2100 GMT May 7), according to the Kremlin.

The Kremlin said that Putin had ordered a full cessation of hostilities to mark the 80th anniversary of Russia's Victory Day, which falls on May 9.

Russia called on Ukraine to join the truce, it said, adding that Russian troops would give "adequate and effective response" if Ukraine violates the ceasefire.

The Kremlin noted that Russia "once again declares its readiness for peace talks without preconditions."

READ MORE: Lavrov: Russia ready to reach Ukraine deal, details still under discussion

Meanwhile, Russian Foreign Minister Sergey Lavrov said Russia remains "open to negotiations" on Ukraine and expects "readiness" from Ukraine.

In a written interview with Brazilian newspaper O Globo posted on the foreign ministry's website Monday, Lavrov said that Washington has become more aware of Russia's stance on Ukrainian settlements through its contacts with Moscow.

ALSO READ: Russia detains man suspected of killing senior army officer

Lavrov held a telephone conversation with US Secretary of State Marco Rubio on Sunday. Both sides stressed the importance of consolidating the emerging prerequisites for starting peace talks on Ukraine, according to a press release from the ministry.

Kremlin Spokesman Dmitry Peskov said Monday that Putin "has repeatedly confirmed the readiness of the Russian side to start the negotiation process with Ukraine without any preconditions."