Ukraine is preparing to present a revised peace plan to the White House, as it seeks to avoid making territorial concessions to Russia.
Kyiv is set to propose alternatives after President Volodymyr Zelensky again ruled out surrendering land, saying he had "no right" to do so under Ukrainian or international law.
He made the comments after meeting European and Nato leaders on Monday, part of a push to deter the US from backing a peace deal which includes major concessions for Ukraine, and which allies fear would leave it vulnerable to a future invasion.
The Ukrainian president told a news conference his team could send a new proposal to the Americans as soon as Tuesday, AFP news agency reported.
Zelensky's ongoing diplomatic tour of Europe follows intensive talks between US and Ukrainian negotiators over the weekend which failed to produce a deal to which Kyiv could agree.
