The process for Moscow and Kiev to develop a unified text of a peace and ceasefire memorandum will be complex, so there can be no fixed deadline, Russia's news agencies cited Kremlin spokesperson Dmitry Peskov as saying in remarks.
"There are no deadlines, and there cannot be any. It is clear that everyone wants to do this as quickly as possible, but, of course, the devil is in the details," RIA state news agency quoted Peskov as telling reporters early on Tuesday.
"The drafts will be formulated by both the Russian and Ukrainian sides, these draft documents will be exchanged, and then complex contacts to develop a single text," the Kremlin spokesman said.
US President Donald Trump held calls on Monday with Russian President Vladimir Putin, Ukraine's President Volodymyr Zelenskyy and the leaders of the European Union, France, Italy, Germany and Finland in an attempt to advance peace in the three-year-old war in Ukraine.
Trump said after the call that Russia and Ukraine will immediately start ceasefire negotiations.
Putin said Russia "is ready to work with the Ukrainian side on a memorandum on a possible future peace accord."
The US president also said it would be great if both countries hold truce talks in Vatican, which would ease some of the bitterness.
Russian leader says ceasefire with Kiev possible upon reaching relevant agreements, Russia and Ukraine must find compromises that suit both sides.