India, Oct. 25 -- Ukraine and Russia have signalled their willingness to resume US-brokered peace talks and are backing a humanitarian mission led by First Lady Melania Trump. But deep disagreements over territory and security guarantees that re-emerged this week underscore obstacles to ending the war.

The new diplomatic push comes after more than 4½ years of fighting, bringing with it a surprise announcement on Friday: Kyiv and Moscow have agreed to a local ceasefire to allow aid next week into a stranded town in Ukraine's southern war-divided region of Kherson, following secret consultations between Melania Trump and civilian negotiators from Russia and Ukraine. While the initiative raised hopes of similar humanitarian missions in...