Admiral Eric T Olson, head of US Special Operations Command, speaking to the Subcommittee on Terrorism, Unconventional Threats and Capabilities, said his elite special operations forces can't grow fast enough to meet increasing global demands, so the Pentagon is depending more heavily on support that is not always available from regular forces.

Adm Olson turned to intelligence concerns in North Africa in response to a question from Rep Adam Smith, D-Wash., chairman of the House Armed Services terrorism subcommittee.

Mr Smith asked Adm Olson if the special operations forces could use more intelligence and surveillance coverage in North Africa, where Al-Qaeda has set up a franchise in the vast ungoverned areas.

'We've got to find ways of having a better understanding of what is happening there,' Adm Olson said, adding that increased surveillance would be one answer.

In Pakistan, Adm Olson said the US must be careful not to take any action that suggests that the Pakistan military is an extension of the US military.

And in Afghanistan, he said, the key is to have as small a footprint as possible, and work 'village by village, valley by valley.'

'The non-availability of these force enablers has become our most vexing issue in the operational environment,' Adm Olson said.

Special operations forces can only grow by 3 per cent to 5 per cent a year, Adm Olson said. But the need for those units to deploy in hot spots around the globe is outpacing that growth, he said.

The mobile, specially-trained units carry out more secretive anti-terror missions, and in a number of countries they are used to train foreign forces. -- AP