The US and allied nations have launched the first air strikes against Islamic State (IS) militants in Syria, the Pentagon has said.
Spokesman Rear Adm John Kirby said fighter and bomber jets and Tomahawk missiles were used in the attack.
US and Allied Nations Launched Airstrikes in Syria Against Islamic State militants
The strikes were expected as part of President Barack Obama's pledge to "degrade and destroy" IS, which has taken huge swathes of Syria and Iraq.
The US has already undertaken 190 air strikes in Iraq since August.
The jihadist group has taken control of portions of a vast area between Syria and Iraq.
On Monday, Rear Adm Kirby confirmed "US military and partner nation forces" were undertaking military action in Syria but did not give details.
"Given that these operations are ongoing, we are not in a position to provide additional details at this time," he said in a statement.
source: bbc news