A Downing Street spokesperson said:

The Prime Minister spoke to President Obama on Friday 4 December. The Prime Minister offered his condolences over the recent San Bernardino shootings.

President Obama congratulated the Prime Minister on the outcome of this week’s vote on Syrian airstrikes, noting the UK would play an important part in ensuring the ultimate defeat of Daesh.

The Prime Minister explained we were increasing the number of Tornado aircraft deployed in the region and sending a new squadron of Typhoon to strike Daesh targets inside Syria. We stood ready to do more to support the Global Coalition campaign against Daesh.

The Prime Minister and the President agreed on the need for progress on the political track and the importance of engaging with Russia and Iran as part of this.