U.S. Secretary of State John Kerry says other members of NATO have voiced a willingness to do more in the fight against Islamic State (IS) militants.
Kerry was speaking on December 2 in Brussels where NATO foreign ministers have been holding two days of meetings.
Kerry said he asked the NATO foreign ministers to do more to strike at IS's core in Iraq and Syria and strangle its international networks.
He said several countries are bringing more to the battle or will do soon, but failed to outline any concrete new commitments.
Germany recently approved sending forces and materiel for non-combat support roles near the Middle East. A British vote is expected later on December 2 on expanding that country's air strikes against IS into Syria.
Kerry said other countries would come forward with new plans after further discussions at home.
Kerry lauded Cameron's decision to go to parliament and seek approval for British strikes against IS in Syria.
"This is a very important step. We applaud his leadership," Kerry told reporters.