Donald Trump called Vladimir Putin to offer condolences over the deadly St Petersburg tube bombing.
The Kremlin said the president offered sympathy to the families of the victims of Monday's blast and asked his Russian counterpart to convey his support to the Russian people.
Mr Putin thanked Mr Trump for the expression of solidarity, saying the two leaders share a view that 'terrorism is an evil that must be fought jointly'.
The blast ripped through an underground train in St Petersburg, Russia's second-largest city, killing 14 and wounding 49.
Mr Putin was visiting the city, his home town, at the time.
Mr Trump said it was 'absolutely a terrible thing', White House press secretary Sean Spicer said. He said the US was prepared to offer assistance to Russia.
The official call between the two leaders was the first since shortly after the billionaire TV personality took office - when Mr Trump spoke with Mr Putin as well as four other world leaders in the same day.