KYIV -- Ukrainian Presidential Advisor Mykhailo Podolyak said that Kyiv insists on a system of security guarantees for Ukraine as one of the key elements of negotiations with Russia, the presidential press service reported Saturday.

During an interview with German media, Podolyak stressed that such a system "is impossible without the participation of the United States in the first place."

According to the negotiator, the future of Crimea, certain areas of Donetsk and Luhansk should be decided only by the presidents of Ukraine and Russia.

He called on Ukraine's partners to provide air defense systems, give weapons to "adequately help" Kyiv, adding that sanctions, such as oil embargoes and restrictions on financial transactions, are also needed.

Earlier this month, Podolyak said that Ukrainian President Volodymyr Zelensky and his Russian counterpart, Vladimir Putin, may hold talks soon.

But Kremlin spokesman Dmitry Peskov said Monday that it is too early to talk about a meeting between the two presidents, as there is no breakthrough yet in the peace talks.

Ukrainian and Russian delegations held three rounds of peace talks in-person in Belarus since Feb 28, and the fourth one started on March 14 in a format of video conference.