MOSCOW, May 14 (Reuters) - Yevgeny Prigozhin, the head of the Wagner mercenary force, offered to reveal the position of Russian troops to the Ukranian government, the Washington Post reported on Sunday, citing leaked U.S. intelligence documents.

Wagner's soldiers have been at the forefront of a bloody Russian offensive to take the city of Bakhmut. In exchange for Ukraine withdrawing its soldiers from the area, Prigozhin in January offered to tell its intelligence service the positions of Russian forces, the Post reported.

The paper said Ukraine rejected the offer.

Prigozhin, a close ally of Russian President Vladimir Putin, has publicly threatened to withdraw his mercenaries from the area around Bakhmut, where they are at the vanguard of the Russian offensive, unless they receive much-needed ammunition.

He said Tuesday in an audio message that he and his men would be regarded as traitors if they abandoned the area.

The Post reported Prigozhin's offer came through his contacts with Ukraine's intelligence service.

A White House spokesman declined to comment on the report, which was based on secret U.S. documents leaked to the group-chat platform Discord.