Boris Johnson has urged his Russian counterpart to take action to halt the assault on Aleppo.
The Foreign Secretary spoke to Sergei Lavrov and called on Moscow to use its influence to halt the bombardment and allow vital aid supplies in to the besieged Syrian city.
The telephone conversation came after Mr Johnson told MPs that Britain and its allies must "reach out to the Russians" to persuade Vladimir Putin's administration to deliver a ceasefire.
A Foreign Office spokeswoman said: "The Foreign Secretary spoke to Russian Foreign Minister Sergei Lavrov this afternoon.
"The Foreign Secretary reiterated the UK's concern about the grave humanitarian situation in Syria, and urged Russia to use its influence with the Syrian regime to stop the assault on Aleppo and allow aid into the city.
"The Foreign Secretary also expressed concern about the deteriorating security situation in Ukraine, and continued Russian support for the separatists.
"Both ministers agreed on the need for ongoing dialogue on key international and bilateral issues."
Earlier, Mr Johnson told MPs: "We're working hand in glove with the United States to try to bring a ceasefire in Aleppo.
"I last had a conversation with (US Secretary of State) John Kerry on this matter very recently.
"Alas, it has proved impossible so far to persuade the Russians to drop their support for their Syrian client, but they have the opportunity to do just that.
"We need to reach out to the Russians and show it's up to them now to show the leadership the world expects to call for a ceasefire in Aleppo, to deliver a ceasefire in Aleppo, to let the humanitarian aid get through and to prevent a catastrophe for the people of that city over the winter months."
Theresa May last week raised the possibility of sanctions if Moscow was found to have broken humanitarian laws in Syria.
The Prime Minister, speaking after talks in Berlin with the leaders of the US, Germany, France, Italy and Spain, said: "We agree on the need to keep up the pressure on Russia, including the possibility of sanctions on those who breach international humanitarian law."