US President Donald Trump is considering ideas such as a "tariff-free zone" for Ukraine to boost its economy as Washington remains hopeful it will help end Russia's all-out war in Ukraine, US envoy Steve Witkoff said in Davos on Thursday.
"The president has talked about a tariff-free zone from Ukraine that I think would be game-changing," Witkoff said at the Ukrainian Breakfast on the sidelines of the World Economic Forum in the Swiss Alps resort town.
"I think we made a lot of progress. I think in the beginning of this process there was a little bit of confusion," he said.
"I was going to Moscow quite a bit, but I think it was important that we go there because we're at the end now and I actually am optimistic," Witkoff added.
Witkoff said that negotiations for a peace settlement were now down to one final issue, without clarifying what that was.
The US has held talks with Russia as well as with Ukraine and European partners on various drafts of a plan to end Russia's war in Ukraine, but so far a deal has remained elusive.

"If both sides want to solve this, we're going to get it solved," Witkoff said.
On Wednesday, Trump said that the leaders of Russia and Ukraine would be "stupid" if they failed to get a deal done.
Witkoff, speaking at the event alongside NATO chief Mark Rutte and Finland’s President Alexander Stubb, said he would be heading to Moscow later on Thursday.
But the Kremlin on Thursday gave a lukewarm response to Witkoff's comments that a peace deal was close.
"Discussion will continue on the Ukrainian settlement issue and other related topics," Kremlin spokesperson Dmitry Peskov told reporters.
He said US representatives, including Witkoff and Trump's son-in-law Jared Kushner, are expected to arrive in Moscow late on Thursday afternoon and will meet Russian President Vladimir Putin.

In November, the US presented Ukraine with a draft 28-point peace plan, reportedly drafted by Witkoff and Kushner.
That proposal was criticised by Ukraine and its Western allies as being too favourable towards Russia and its maximalist demands.
Peace negotiations
In December, Zelenskyy countered with a 20-point plan of his own, saying it would be accompanied by a three-way security agreement involving the US and the EU, a separate Ukraine–US security agreement, and a Ukraine–US economic agreement.
Security guarantee plans with EU countries would include Ukrainian forces as the first line of defence, European-led troops deployed in Ukraine and US security guarantees, according to Ukrainian negotiator Oleksandr Bevz.
An economic support package of about €682 billion for Ukraine over the next 10 years has been agreed to by international partners, Ukraine’s Deputy Prime Minister Taras Kachka said.

The sum, based on calculations by the World Bank, the IMF and the EU, is meant to cover damage compensation, reconstruction, economic stability and a €170 billion growth "booster" linked to reforms required for Ukraine’s EU accession.
US security guarantees for Ukraine have been outlined for a period of 15 years, with the possibility of extension, Zelenskyy told journalists in December.
"We have great achievements, the 20-point peace plan is 90% agreed and US-Ukraine security guarantees are 100% agreed," Zelenskyy told reporters. "US, Europe and Ukraine security guarantees are almost agreed. The military dimension is 100% agreed."
But a sticking point remains around the fate of the Ukrainian territories that Moscow occupies, which it insists it must keep in the event of any ceasefire deal. The Kremlin has also said it would accept Western troops stationed in Ukraine.