The Pentagon will reduce its naval presence in the Gulf to one aircraft carrier group by August, defence officials said.

The US Defence Department said the move did not reflect a change in its concerns about the Middle East and that its naval presence in different regions changes periodically.

 'This change in carrier presence does not reflect a change in commitment or concern for the region,' Pentagon spokesman Bryan Whitman said.

'Carrier presence is but one means by which the US engages in the region.'

Defence Secretary Robert Gates decided in January to boost the US naval presence in the Gulf to two aircraft carriers and their escort ships, which officials said was meant to reassure US allies worried about Iran's growing influence.

Rotation and maintenance schedules, however, force the Navy to drop to one carrier group in the Gulf as soon as August, according to defence officials.

Those officials also said there could be five-day window before the year's end when no US carriers are in the Gulf. Whitman would not comment on specific deployment timetables.

To maintain two carrier groups, Gates would have to had to intervene in planned rotation schedules. Reuters