KYIV (Reuters) - Ukrainian officials have already started preparatory work to organise a second peace summit, the Ukrainian president's chief of staff Andriy Yermak said on Tuesday, after the first conference led by Ukraine was held last weekend in Switzerland.

Yermak told an online press briefing late on Tuesday evening that the summit would only be possible after a joint plan had been figured out by member states, a process which he expected to take several months.

"The second summit will be possible when we have a joint plan," he said, adding that a lot of work remained to be done.

A summit hosted by Switzerland over the weekend saw over 90 countries attend, but Ukraine and its allies failed to persuade major non-aligned states to join their final statement, and no country came forward to host a sequel.

Moscow was not invited to the event. Yermak said a Russian representative could be invited to the second such summit to be presented the peace plan decided upon by the event.

Russia launched a full-scale invasion of Ukraine in 2022, igniting the bloodiest conflict in Europe since World War Two. It has demanded Ukraine give up land and its ambition to join NATO in exchange for peace talks, conditions which Kyiv rejects.

(Reporting by Max Hunder; Editing by Stephen Coates)