(Recasts with comment about troop contingent in paragraphs 1-6; changes keywords used by some media clients to match visuals)

KYIV, Dec 9 (Reuters) - Ukrainian President Volodymyr Zelenskiy floated the idea on Monday of foreign troops being deployed to war-stricken Ukraine until the country joins the NATO military alliance.

He made the remark during a joint press conference in Kyiv with German opposition leader Friedrich Merz, as Donald Trump's imminent return to the White House intensifies talk of a possible deal to end

Russia's 33-month-old war

.

Ukraine, which has made a concerted push to obtain an invitation to join NATO, has insisted throughout the war that it needs security guarantees to prevent Russia launching another invasion after the current hostilities are halted.

"A troop contingent from one country or another could be present in Ukraine for as long as it isn't part of NATO. But for that we need to have a clear understanding of when Ukraine becomes an EU member and when a NATO member," Zelenskiy said.

French President Emmanuel Macron caused controversy in Europe in February when he raised the possibility of European nations

sending troops to Ukraine

, although he cautioned that there was no consensus on the matter.

"Even if we get invited (to NATO), what happens then? Who guarantees our security? We can think about that and work on Emmanuel Macron's proposal," Zelenskiy said.

The Ukrainian leader told reporters he was hoping to call outgoing U.S. President Joe Biden in the coming days to discuss NATO membership.

"I intend to call President Biden in the coming time to discuss the question of an invitation to join NATO," he said through an interpreter.

"He is the current president and a lot rides on his opinion. Discussing it with Trump before he takes office doesn't make so much sense."

Russia has demanded that Ukraine abandon its NATO ambitions and sees Kyiv's membership of the alliance as an unacceptable security threat.

(Reporting by Andreas Rinke in Kyiv and Yuliia Dysa in Gdansk; writing by Tom Balmforth, editing by Alex Richardson)

((Tom.Balmforth@thomsonreuters.com))