Washington: About a dozen US fighter jets will be flying and conducting training operations in Jordan, poised to respond if needed to protect allies if the war in neighbouring Syria spills over the border, US administration officials said on Friday.

The increased show of US military might — which brings the total number of US forces in Jordan to 1,000 — should be seen as a signal to Syria that it must confine its two-year-old civil war within its borders, officials said. The officials said it is meant to show that the US is committed to its defence relationship with Jordan and that America intends to maintain a strong presence in the region. The officials added, however, that the decision to keep the F-16 fighters there is not a first step toward establishing a no-fly zone around any parts of Syria and should not be interpreted as a move to begin staging American troops there for possible military action in Syria. The officials spoke on condition of anonymity because they were not authorised to discuss the mission publicly.

The F-16 fighters, along with a Patriot missile battery and about 700 US troops, are staying in Jordan beyond an international military exercise, which ended this week. The decision significantly increases the number of US troops in Jordan, adding to the approximately 250 that have been there for some time.

Jordan had asked the US to leave some military troops and equipment behind. The US troops were in Jordan for a 12-day military exercise, dubbed Eager Lion, which ended this week. It included land, air and sea manoeuvres across the country and involved personnel from 19 Arab and European nations.