BERLIN — NATO’s secretary-general said Thursday that he hopes for a decision by the time member countries’ leaders meet May 25 on whether the alliance formally joins the coalition fighting the Islamic State group.

The U.S. under President Donald Trump is keen for a greater emphasis on NATO fighting terrorism. NATO chief Jens Stoltenberg said that all members of the 28-alliance are already members of the anti-IS coalition, though NATO itself formally isn’t.

“The question is whether NATO as an alliance should be at the table coordinating with the others, or whether we should continue to provide support to the coalition,” Stoltenberg said after meeting German Chancellor Angela Merkel.

If it does join, “it will not change the fundamental role of NATO, because we will not be engaged in combat operations — neither in Syria nor Iraq,” it said.

NATO currently provides support with AWACS surveillance planes and with training in Iraq, in addition to what its member nations provide individually.

Merkel was noncommittal on whether NATO should formally join the coalition, saying that she had “encouraged” Stoltenberg to pursue talks on the matter. She stressed that the possible move wouldn’t lead to Germany expanding any military activity.

NATO is also considering at present whether to send several thousand more troops to Afghanistan but, as at present, not in a direct combat role.

Germany is one of the major contributors to the NATO-led Resolute Support mission, with 964 soldiers. Merkel said: “I don’t see us in the front row, and I don’t have any concrete plans” as far as increasing that number is concerned.

Stoltenberg said decisions will be made “within weeks” on requests from military authorities for more troops.

“If there is any increase, which is not yet decided, then we will go out and ask all allies and partners,” he said.

NATO currently has about 13,000 troops in Afghanistan, more than half of them American.

Alliance members’ leaders will meet in Brussels May 25.