The Ukrainian Foreign Minister Pavlo Klimkin and US Secretary of State John Kerry met in Washington on Tuesday.
Kerry announced the US would give 7 million dollars to help rebuild eastern Ukraine.
Both men called for an end to the fighting near the site of the Malaysian plane crash.
“The site has to be cordoned off. The evidence has to be preserved and Russia needs to use its considerable influence among separatists in order to be able to help ensure this basic approach of common decency,” said Kerry.
Klimkin agreed, saying: “For us it’s a matter of human dignity, it’s about the possibility of recovering all bodies and body fragments of the crash site, it’s about giving back to friends and loved ones any sort of belongings”
Meanwhile Moscow has urged Kyiv to halt military activity near the site and said that OSCE monitors must be deployed near the Russian-Ukrainian border.