"There is, of course, inertia in this process," Peskov said, referring to the prolonged absence of a meeting between Russia's President Vladimir Putin and US President Donald Trump, Reuters reported.
"It takes time for efforts to bring bilateral relations back onto a normal track."
TASS reported that for the first time in modern Russian history more than six months have passed since a new US president's inauguration without a summit with the Russian leader.
US special envoy Steve Witkoff is expected in Moscow on Wednesday to meet with Russian leadership in an effort to bring the war in Ukraine to an end.
Russia-US ties have been marked by escalating tensions in recent weeks, with Trump saying he had ordered two nuclear submarines to be positioned in "the appropriate regions" in response to remarks by former Russian president Dmitry Medvedev.
Trump has also issued an ultimatum to Putin, demanding a ceasefire in the war and a formal peace agreement by Aug. 8.
Trump threatened to hit Russia with new sanctions and impose 100% tariffs on countries that buy its oil - of which the biggest are China and India - unless Putin agrees to a ceasefire in the war.