The European Union's chief diplomat said on Monday that peace efforts to end Russia's war in Ukraine could enter into a decisive phase after a new round of talks between the US and Ukraine over the weekend.

Axar.az informs, citing DPA, "It could be a pivotal week for diplomacy," Kallas told journalists in Brussels, arriving at a meeting of EU defence ministers.

"We heard yesterday that the talks in America were difficult but productive," she said, adding that she will talk to Ukraine's foreign and defence ministers during the day.

One controversial point under discussion between Washington and Kiev have been possible future limitations on the size of Ukraine's armed forces.

Kallas rejected the idea saying "the Russian army is the one that is actually a risk to everybody."

"If Russia's army is big, if their military budget is as big as it is right now, they will want to use it again," she warned.

Kallas dodged a questions by a journalist on whether she trusts the US administration to find a good solution for Ukraine.

"[The] Ukrainians are there alone. If they would be together with the Europeans, they would definitely be much stronger. But I trust that Ukrainians stand up for themselves," she replied instead.