Ukraine’s sports minister on Wednesday urged the country’s athletes to avoid Russians at the upcoming Olympics in Beijing, amid fears that Russia might invade its ex-Soviet neighbour.

Kyiv and Moscow have been at loggerheads since Moscow annexed Crimea and backed a separatist uprising in eastern Ukraine in 2014, starting a conflict that has claimed more than 13,000 lives.

Tensions peaked after Western governments accused Moscow of amassing over 100,000 troops on Ukraine’s border in recent months and warned it could be planning an attack.

Sports minister Vadym Guttsayt said Wednesday that during a “patriotic” meeting athletes and coaches were instructed to avoid the Russian Olympic delegation.

They were told to “avoid standing with Russian athletes and not take photos”, he told the online outlet Tribuna.com.

“The war has been going on for eight years, now it is an aggravation of the situation on the border. It is very important that our athletes really control their emotions in such situations,” he said.

Guttsayt said he cannot “force” them to avoid Russians, but his ministry “recommends” that the 45 Ukrainian athletes travelling to Beijing do so.

“I understand that for many years there have been friendships between athletes who train together. But . . . this is the country with which we are at war,” he said.

The minister added that everyone “agreed and heard” the message following the meeting.

Earlier on Wednesday, Kyiv mayor Vitaly Klitschko, a former world heavyweight champion boxer, pledged to “defend” the city, if warnings of a potential invasion by Russian forces come true.

Ukraine’s Western allies warned that they will slap harsh sanctions should Moscow attack Ukraine. The Kremlin has denied any plans to invade.