The United Nations’ humanitarian chief is not optimistic about securing a ceasefire to halt the fighting in Ukraine, he said Thursday following high-level talks in Moscow and Kyiv that underscored how far apart the two sides are.

Undersecretary-General Martin Griffiths gave the bleak assessment in an interview with The Associated Press in the Ukrainian capital after wrapping up talks with Prime Minister Denys Shmyhal and other top officials. That followed discussions with Russian Foreign Minister Sergey Lavrov and officials in Moscow earlier in the week.

“I think it’s not going to be easy because the two sides, as I know now ... have very little trust in each other," he said.

“I'm not optimistic,” he added later.

U.N. Secretary-General Antonio Guterres dispatched Griffiths to the Russian and Ukrainian capitals to explore the possibility of establishing a cease-fire that would allow desperately needed aid into Ukraine and potentially lay the groundwork for talks aimed at ending the war.

Griffiths suggested that goal remained far in the distance.