UK's Johnson visits Moscow amid strain in ties with Russia

British Foreign Secretary Boris Johnson is in Moscow amid an acute strain in ties between Britain and Russia.

Johnson is the first foreign secretary to visit Russia in more than five years, reflecting tensions over Ukraine and other issues.

Relations have also been strained by the 2006 poisoning death of ex-Russian spy Alexander Litvinenko.

Despite the differences, Johnson stressed the need for the two nations to cooperate on tackling international challenges, such as preserving the Iran nuclear deal and dealing with the crisis over North Korea.

He said Friday at the start of his talks with Russian Foreign Minister Sergey Lavrov that the two countries cooperate on security preparations for next summer's World Cup hosted by Russia.