Islamabad, April 23: Financial constraints have forced Pakistan to halve to 18 the number of F-16 combat jets it is buying from the US, a media report Wednesday said.

Pakistan had earlier sought to buy 36 F-16 Block 50/52 aircraft for $5.1 billion, which included associated weapons, spares and upgrading of an earlier fleet purchased in the 1980s.

"The decision to reduce the order by half would also halve the cost of the aircraft and that of the weapons associated with them," Dawn reported Wednesday in a dispatch from Washington.

Pakistan, however, will still have to spend $1.3 billion on the mid-life update and modification of the F-16A/B aircraft purchased earlier. Engine modifications and purchase of equipment for the old fleet will cost another $151 million.

Quoting sources, Dawn said the new aircraft will be fully equipped with weapons and facilities that come with a F-16 Block 50/52 aircraft. The planes will be capable of carrying nuclear and non-nuclear weapons.

The US will, however, have the right to conduct frequent inspections and inventory checks with relation to the aircraft.