A US reconnaissance aircraft (file photo)

The United States has flown a spy aircraft over eastern Ukraine to gather intelligence about Russian activity, even as Washington and Moscow prepare for talks intended to defuse tensions that have raised fears of a conflict.

Lieutenant Commander Russ Wolfkiel, a spokesperson for US European Command, told CNN on Wednesday that the US Air Force had flown an E-8C Joint Surveillance Target Attack Radar System (JSTARS) aircraft over Ukraine earlier this week, marking one of the first reconnaissance missions that the US military has openly carried out within Ukrainian air space.

Wolfkiel said the US routinely operates aircraft in the Black Sea region in support of various US and coalition intelligence objectives, without revealing the exact route of the aircraft and the details of the intelligence allegedly gathered during the flight, which was carried out with Ukraine�s permission on Monday.

He said the spy plane had stayed out of the Donbass region, where ethnic Russians demanding independence from Ukraine operate, but it had potentially been able to observe military activities on both sides of the country�s border with Russia.

The E-8C JSTARS aircraft are military versions of the Boeing 707-300, able to provide battle management, command and control, reconnaissance, and surveillance capabilities.

The latest development comes amid continued tensions over Ukraine. Western countries accuse Russia of preparing for an invasion of Ukraine by amassing troops and weapons near the border with the country. Moscow, however, says it is entitled to move its military freely within its borders and that it is taking precautionary measures because of increased NATO activity near its territory.

The US and its European allies have promised to impose harsh economic sanctions if Russia attacks Ukraine.

Meanwhile, US President Joe Biden is planning to hold a call with his Russian counterpart, Vladimir Putin, on Thursday afternoon to discuss a range of topics, including upcoming diplomatic engagements with Russia, National Security Council spokesperson Emily Horne announced on Wednesday.

American and Russian officials are also expected to hold talks on January 10 to discuss European security and simmering tensions over the Ukraine conflict.

Earlier in the month, Russia unveiled a list of security proposals it wants from the US, including a pledge that NATO would give up any military activity in Eastern Europe and Ukraine.

On Monday, Biden signed a bill to provide $300 million in support for Ukraine�s armed forces.

US Defense Secretary Lloyd Austin has also ordered the US navy�s Harry S. Truman Strike Group on Tuesday to remain in the Mediterranean rather than sail to the Middle East in order to reassure European allies of US military support.