The US and allies said to include Arab nations have launched the first air strikes against Islamic State (IS) militants in Syria, the Pentagon says.
Spokesman Rear Adm John Kirby said fighter and bomber jets and Tomahawk missiles were used in the attack.
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 launched 190 air strikes in Iraq since August.
However, Monday’s action expands the campaign against the militant group across the border into Syria.
Rear Adm Kirby confirmed the strikes, saying “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.
The Syrian government has not formally consented to the air strikes on its territory. However, it says it was informed before they took place.