WASHINGTON - Russian authorities have confirmed that a group of diplomats expelled from the United States have boarded a special flight and are on their way home.

A spokesman for Russia’s Embassy in the US said Sunday that the diplomats, who were accused of espionage and were asked to leave the US soil earlier in the week, had departed from Washington’s Dulles International Airport and were heading to Moscow.

“The plane has taken off,” Nikolai Lakhonin said, adding that the all the diplomats that had been expected to leave the US by January 1 were on the flight. Moscow had earlier sent a special plane to evacuate the diplomats and their families. The 35 staffers were ordered by US President Barack Obama to leave the country on December 29 after accusing them of engagement in espionage for Russia.

The case was related to the alleged cyber attacks against US Democrats during the 2016 presidential election. Obama also imposed sanctions on two Russian intelligence agencies while ordering the closure of two Russia-owned recreational compounds.

The hacking allegations against Russia are the latest episode in the already strained relations between Washington and Moscow. The two have been at odds over the conflicts in Syria and Ukraine. The Russian government said after the expulsions of the diplomats that it would delay a potential retaliation until President-elect Donald Trump takes office on January 20. Russian President Vladimir Putin has hoped for a restoration of ties under Trump, who hailed Putin’s decision not to retaliate and has generally rejected the notion that Russia was involved in the hacking that many say helped him win the US election.