Kyiv has now expressed readiness to drop its bid to join the NATO military alliance if the U.S. and other Western nations give it similar security guarantees.

Russian Deputy Foreign Minister Sergey Ryabkov told ABC News during an exclusive interview in Moscow on Monday that he believes the warring parties are close to a deal.

President Donald Trump has directed U.S. officials to help to facilitate a “lasting and durable peace" between Ukraine and Russia, with a "very, very strong" package being presented.

Two days of intense negotiations between Ukraine, the U.S. and European officials resulted in clear progress on security guarantees for Ukraine but left significant gaps on the issue of territory, U.S. officials told reporters on Monday.

A 1,000-strong "dark fleet" of rogue tankers evading sanctions has become a new target for the U.S. and Ukraine, according to a senior maritime intelligence analyst.

European leaders said they had agreed on Monday any decisions on potential Ukrainian territorial concessions to Russia could only be made once robust security guarantees were in place which should include a European-led multinational force.