President Volodymyr Zelensky has suggested that the parts of Ukraine under his control should be taken "under the Nato umbrella" to try and stop the "hot phase" of the war.
In a long, wide-ranging interview with Sky News, the Ukrainian president was asked whether he would accept Nato membership, but only on the territory that Kyiv currently holds.
Zelensky said he would, but only if Nato membership was offered to the whole of Ukraine, within its internationally recognised borders, first.
Ukraine could then attempt to negotiate the return of territory currently under Russian control "in a diplomatic way", he said.
But the suggestion is highly theoretical. As Zelensky pointed out, no-one has yet made such an offer.
Whether Nato would ever consider such a move is highly doubtful.