Russia launched attacks on Ukraine's capital with at least six people killed in strikes that hit city buildings and energy infrastructure. The attacks came during a renewed U.S. push to end the war.

Kyiv and its allies voiced optimism Tuesday that talks with an American delegation had produced changes to the plan, while the Kremlin said it was waiting to hear more.

A missile-and-drone barrage killed at least six people in Ukraine’s capital, officials said, hours after officials said they had made some headway on a peace proposal.

The calls for a peace deal came as Russia launched a wave of attacks on Ukraine's capital, Kyiv, overnight, with at least seven people killed in strikes that hit city buildings and energy infrastructure.

Crucial input from a Kremlin confidant influenced the document that for a week roiled relations between the U.S., Ukraine and Europe.

US army secretary Dan Driscoll arrived in Abu Dhabi on Monday for talks with Ukraine’s military intelligence chief and a Russian delegation as Washington pushes a peace deal to end the Kremlin’s war.

Russian Foreign Minister Sergei Lavrov said on Tuesday that an amended peace plan for Ukraine must reflect the "spirit and letter" of an understanding reached between President Vladimir Putin and U.S.

Ukraine did not react positively to the peace deal brokered through the U.S., prompting European leaders to craft a counter-offer.

Top U.S. and Ukrainian officials said Sunday they were making progress toward ending the Russia-Ukraine war but provided scant details as they discussed the American proposal to achieve peace despite concerns among many of Washington's European allies that the plan was far too conciliatory to Moscow.