GENEVA: Russian and US diplomats held talks behind closed doors in Geneva on Thursday which both sides described as constructive, in the latest round of discussions aimed at ironing out the many tensions between the world's top two nuclear powers.

US State Department number two Wendy Sherman and Russia's deputy foreign minister Sergei Ryabkov met for most of the day, with both sides saying they would continue discussions on arms control.

In a joint statement after the talks, the State Department and the Russian foreign ministry said the two delegations had agreed to form two working groups, one of which will look at future arms control measures.

"The delegations additionally agreed that the two working groups would commence their meetings, to be followed by a third plenary meeting," the statement said.

Ryabkov said that the sides had discussed the "entire range of issues" related to strategic stability and arms control.

"Despite existing differences -- and there are a lot -- there is a desire and readiness to move the process further," he was cited by Russian news agencies as saying.

"This is slow progress. But this in itself is also good."

A senior State Department official said that the meeting was "very interactive and broad-based" and went in-depth into multiple issues, although she declined to give details.

"We think this was a very productive meeting," she told reporters on condition of anonymity.

   **- 'Sort of pact' -**

While the United States and Russia are set to negotiate a successor to the New START nuclear treaty, the official said that the talks also discussed broader confidence-building measures and conventional weapons.

"The simple act of dialogue is sort of part of arms control," she said.

"There are non-nuclear tools that can have strategic implications and that's really sort of a conversation that we'd like to expand -- both Washington and Moscow -- and sort of understanding threat perceptions and where we think we need to go in that space."

In June, US President Joe Biden and Russian counterpart Vladimir Putin met in a high-profile summit at which they agreed it was vital to keep talking despite the differences that divide them.

From cyber attacks on US entities and meddling in the last two US presidential elections to human rights violations and aggression against Ukraine and other European countries, the US list of allegations against the Kremlin runs long.

Putin though insists he is just challenging US hegemony, and has denied any connection to what the US says are Russia-based hacking and ransomware gangs, or having any hand in the deaths of many opponents during two decades in power.

Thursday's talks were held at Russia's UN mission, after the last round in late July was hosted by the Americans a few hundred metres (yards) away.

Arms control was at the top of the agenda at that exchange.