No deal was announced after Washington's talks with both Kyiv and Moscow in Saudi Arabia on Tuesday aimed at pausing the three-year-old conflict in Ukraine, and Russia said it is willing to strike an agreement on the safety of shipping in the Black Sea, but only if Washington ordered Kyiv to respect it.

Officials from the United States and Russia wrapped up their marathon talks on Monday in Riyadh, focusing on a proposal for a naval ceasefire between Kyiv and Moscow.

But Interfax cited Vladimir Chizhov, a senior Russian senator, as telling state TV channel Rossiya-24: "The fact that they sat for 12 hours and apparently agreed on a joint statement, which was not adopted though because of Ukraine's position, is very typical and symptomatic."

Kyiv also held a brief second round of talks with US officials on Tuesday and has not yet commented on the outcome of the talks.

The Black Sea initiative was the priority of discussions at the meeting between US and Russian officials on Monday, Russian Foreign Minister Sergey Lavrov said.

"We will need clear guarantees. And given the sad experience of agreements with just Kyiv, the guarantees can only be the result of an order from Washington to (Ukrainian President Volodymyr) Zelensky and his team to do one thing and not the other. And it seems to me that our American partners have received this signal," he told Channel One TV station.

Earlier on Tuesday, Kremlin spokesman Dmitry Peskov told reporters that the outcome of the US-Russia talks in Riyadh "has been reported in the capitals" and was currently being "analyzed" by Moscow and Washington, but that the Kremlin had no plans to release further details of what was discussed to the public.

"We're talking about technical negotiations, negotiations with immersion in details," Peskov said, adding that while there are currently no plans for Trump and Russian President Vladimir Putin to speak, such a conversation could be quickly organized if the need arises.

"There is an understanding that the contacts will continue, but there is nothing concrete at the moment," he said, adding that that there are no plans to hold a three-way meeting between Russia, the US and Ukraine.

Meanwhile, a Russian negotiator said Moscow would continue "useful" talks with US representatives but would aim to involve the United Nations and other countries.

"We talked about everything, it was an intense dialogue, not easy, but very useful for us and the Americans," Grigory Karasin told the state Tass news agency, adding that "lots of problems were discussed".

In Belgium, the UN's peacekeeping chief said the prospect of deploying peacekeepers to Ukraine under a UN mandate was "very hypothetical" at this stage.

"I think it's fair to say it's very, very hypothetical," Jean-Pierre Lacroix, the UN's under-secretary-general for peace operations since 2017, told reporters when pressed on the matter. "The question is obviously there and it's being asked, and we think of it," he said. "But we're not planning anything."

Any UN peacekeeping mission to Ukraine would first have to receive a mandate from the Security Council, said Lacroix, who said his teams had received no signals "at this stage" in that regard.

cuihaipei@chinadaily.com.cn