Russian diplomats expelled from the United States arrived in Moscow on Sunday, with post-Cold War tensions soaring in the wake of a nerve agent attack on a former spy in Britain.
A deepening crisis in ties between Russia and the West over the past weeks has seen the biggest wave of tit-for-tat diplomatic expulsions in recent memory.
Another salvo in the spat was fired on Saturday, when Russia warned its nationals to think twice before travelling to Britain, where it said they could be singled out for harassment.
By expelling 60 Russian diplomats, the US joined a score of Britain's allies in responding to the poisoning of former double agent Sergei Skripal and his daughter Yulia in the English city of Salisbury on March 4.
Britain has said it is "highly likely" that Russia was responsible for the attack using the Soviet-designed Novichok nerve agent, while Moscow calls the allegations unsubstantiated anti-Russian propaganda.
Two planes arrived at Moscow's Vnukovo airport on Sunday, bringing home a total of 171 people - the 60 diplomats and their families - from Washington and New York.
Russian television showed passengers disembarking from a government plane while several buses waited to pick them up.
The US alleged the 60 diplomats were "spies" and sent them home from posts around the country and at the Russian mission to the United Nations, as well as closing Russia's consulate in Seattle.
Moscow responded by sending home 60 US diplomats and closing Washington's consulate in Saint Petersburg on Saturday.
Washington has since said Russia is free to apply to accredit more diplomats to replace those expelled.
However the furious diplomatic war between Russia and Britain showed no sign of abating as Moscow's embassy in London urged Russians to think carefully before travelling to the UK or sending children to summer school there.
The embassy warned that British authorities including police could single out Russians for additional checks, citing "the anti-Russian policies and an escalation of the British side's threatening rhetoric."
The Russian embassy even urged fans of football team CSKA Moscow flying to London for Thursday's Europa match with Arsenal to exercise "extra vigilance" because of Britain's "anti-Russian campaign."
Britain has acknowledged that border officials searched an incoming Aeroflot flight from Moscow on Friday in what Russia blasted as an act of "blatant provocation".
But Britain said it conducts routine checks on aircraft to protect the UK from organised crime and people attempting to bring harmful substances into the country.
Moscow summoned British ambassador Laurie Bristow on Friday, giving London a month to cut the number of diplomatic staff in Russia to the same number Russia has in Britain.
"Russia suggested parity. The British side has more than 50 more people," foreign ministry spokeswoman Maria Zakharova told AFP.