US President Donald Trump arrives in Turkey to attend NATO summit

US President Donald Trump has landed in the Turkish capital Ankara to attend a two-day NATO summit.

NATO allies showcased surging defence spending with new arms contracts worth billions at a summit in Turkey on Tuesday as they sought to placate US President Donald Trump's fury over Europe's response to the war with Iran.

The two-day gathering in Ankara comes a year after NATO members pledged to ramp up security-related spending to 5% of GDP under pressure from the US leader.

NATO chief Mark Rutte has insisted European countries are "delivering" by bolstering military budgets and moving to take more responsibility for the defence of their continent in the face of Russia.

In bid to impress Trump before he touched down, NATO kicked off with a string of arms announcements at a glitzy defence industry forum ahead of the main summit.

"Allies and industry from both sides of the Atlantic will reveal new major projects and sign contracts worth literally billions of dollars," Rutte said.

"These are billions that are invested in our security, boosting our economies and supporting hundreds of thousands of new jobs."

Among the initial deals announced were contracts for new drones, refuelling, and surveillance aircraft designed to bolster Europe's ability to protect itself.

But Trump, still smarting after European countries restricted US forces from using bases to attack Iran, has spent the run-up to the summit slamming allies for not moving fast enough for his liking.

"Ridiculous for the U.S.A. to continue along this one-sided path when the relationship is not reciprocal. They were not there for us!!!" Trump wrote on Truth Social last week.