US Secretary of State Rex Tillerson is now planning to attend a major Nato summit, despite previously claiming he could not fit the gathering of foreign ministers into his schedule.

The key Donald Trump ally was reportedly intending to miss his first meeting with leaders of the military alliance, that was originally scheduled for early next month.

However, the meeting has now been rescheduled to accommodate Mr Tillerson.

"The Secretary of State will visit Nato in Brussels on Friday, 31 March," a State Department spokesperson said. "The visit will come after his trip to Ankara, Turkey."

The compromise seems intended to allay fears that Mr Trump will try to withdraw funding from the North Atlantic Treaty Organisation (Nato), which he has previously said is "obsolete".

During his presidential campaign, the billionaire said he would "certainly look at" scrapping the entire organisation.

Although he has since rolled back from that position, he has repeatedly said he feels the United States' contributes too much to the organisation when compared with other members.

Shortly after a meeting with German Chancellor Angela Merkel, he claimed Germany owed "vast sums of money to Nato".

He added that "the United States must be paid more for the powerful, and very expensive, defence it provides to Germany!"

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Jorge Benitez, a Director of NATOSource, told The Independent a decision to leave the Alliance would be a "major issue" because "the US plays a leading role in it.

He said it would be "difficult to make important Nato decisions without our top leaders participating and building agreement between the 27 other allies."