The latest draft document on ending almost four years of war with Russia has not been published.

The first version of the US plan, a 28-point text which emerged last week, was widely criticised as heeding Moscow's hardline demands.

"Ukraine, the US and the Europeans have made the American proposal workable," the official said, adding: "It is not 28 points, it has changed significantly significantly for the better."

The official also said the revised plan provides for Ukraine to keep 800,000 troops -- "roughly like it (the army) is now" -- compared to a 600,000 limit in the first draft of the plan.

The official said "sensitive parts" of the plan, such as the issue of territory, could be discussed with US President Donald Trump.

Kyiv is seeking a meeting with Trump, who had initially set a deadline of Thursday this week for agreeing to the first deal that was presented by his government.

"In Abu Dhabi, as I understand it, the Americans are showing the Russians the developed framework," the official said.

The US said earlier it was holding talks with Russian representatives, with an American army spokesman saying they are "going well".