Trump was due to meet NATO leaders in Brussels on Thursday to press his case, with the deadly IS-claimed bomb attack in Manchester high on the agenda.
Earlier today, US Secretary of State Rex Tillerson said he expected NATO to join despite reservations by some members states which are fearful of getting dragged into another conflict.
"The NATO (member state) ambassadors decided this evening an action plan on terrorism for the summit. It includes the accession of NATO to the global coalition against IS," one diplomat said.
"This means that the AWACS will not just do airspace surveillance but airspace management," the diplomat said, asking not to be identified.
"They are going to coordinate the flights and direct airplanes over Syria and Iraq but only for flights which are not related to bombings."
NATO leaders will formally endorse the decision at Thursday's summit, the sources said.
All 28 allies have joined the anti-IS coalition of more than 60 countries, but NATO as an institution has not followed suit up to now despite intense pressure from Washington.
"I have had meetings actually with one of those. I think they're going to support NATO joining and becoming a member of the ISIS fight," he told reporters travelling with Trump.
NATO has baulked at taking on any combat role in the fight against IS and some allies such as France, Germany and Italy have been opposed for fear the alliance would be dragged into a ground war and risk its standing with Arab powers.
"Especially in light of the attack in Manchester, I think it is important to send this message of unity against terrorism."
Trump will also urge the allies to increase defence spending to the target of two percent of a country's annual gross domestic product, as they agreed in 2014.
In return, the allies hope the president will unequivocally state his support for NATO's core Article 5 collective defence commitment.
Asked about this issue, Tillerson said: "Of course we support Article 5. The only time Article 5 has been invoked was in the 9/11" attacks on the United States.
"He is still working on final remarks so I don't want to tell you exactly what is going to be in the speech," he said.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
