Obama's call to Singh takes place close on the heels of the two leaders' meeting in Washington during which the Afghan issue was discussed prominently.
The Prime Minister Office said that during the brief conversation, the two leaders also discussed the forthcoming summit on climate change in Copenhagen.
In Washington, White House spokesman Robert Gibbs said the US president would be making several calls to world leaders to brief them on his new Af-Pak policy.
Gibbs said, "The new Af-Pak policy would come with an exit strategy and will not be an open-ended commitment."
"Ultimately, the strategy will be to transfer the security responsibility of an area to the Afghans," he said.
More than 100,000 US and NATO troops are in Afghanistan, and the president is expected to announce the addition of over 30,000 more US troops to support the war effort.