The agreement could provide a windfall to the U.S., but the resources will be expensive to extract, and any progress is unlikely while the war rages.

Ukraine's prime minister told parliament on Friday that two of the three documents related to a minerals deal with the United States would not need to be ratified, lawmaker Yaroslav Zheleznyak wrote on Telegram.

Ukraine managed to wrangle some more favorable terms out of the United States before signing the long-awaited minerals deal on Wednesday.