US Defence Secretary Ash Carter is expected Thursday to call for greater efforts to defeat Islamic State, at a meeting with his counterparts in the international coalition fighting the extremist militant group in Syria and Iraq.
Several dozen countries back the Washington-led air campaign against Islamic State. Participants include NATO members France, Britain, Canada and Turkey, as well as regional powers Saudi Arabia, Jordan and the United Arab Emirates.
But the United States would like to ramp up the operation and see other countries commit more significantly.
"I don't think anybody's satisfied with the pace of the [campaign]," Carter said on his way to Brussels, where the talks are to take place on the margins of a meeting of NATO defence ministers.
"We do need to accelerate the campaign, and we have a very clear operational picture of how to do it. Now, we just need the resources and the forces to fall in behind it," he added.
In Brussels, Carter will meet among others with Saudi Defence Minister Mohammad bin Salman. The kingdom, along with Bahrain and the UAE, has announced its willingness to send ground troops to fight Islamic State.
Carter welcomed the offer, while adding that there are "lots of different ways" the Sunni Arab allies can contribute.
"I really hope they make a strong contribution, because I think they have a strong stake in making sure that extremism doesn't run rampant over their own region," he said, adding: "It'll [be] good for their futures to be on the winning side."
The defence ministers, who are meeting in that format for the first time since the anti-Islamic State coalition was formed in 2014, are also expected to discuss details of the military campaign.
A lot of the focus is on recapturing Mosul, Iraq's second-largest city that was taken by Islamic State, and al-Raqqa, the group's stronghold in Syria, as soon as possible, "in concert with capable local forces that can ... hold these cities and govern them," Carter said.
An overall 49 countries have been invited to the talks, including all NATO members. The military alliance is not involved in the campaign, but is considering a request to provide air surveillance planes to coalition members, to free up national resources for the fight.
In parallel to the Brussels talks, foreign ministers from countries including the US and Russia are due Thursday to discuss the conflict in Syria, after the latest round of UN-brokered peace talks was suspended amid a flare-up in violence on the ground.