The US should spend much more on diplomacy, economic development and  communicating its message abroad because it cannot win conflicts through military power alone, Defence Secretary Robert Gates said.

'One of the most important lessons of the wars in Iraq and Afghanistan is that military success is not sufficient to win,' Gates told an audience at Kansas State University.

'It is just plain embarrassing that Al Qaeda is better at communicating its message on the Internet than America,' he said in the speech broadcast on the Pentagon's TV channel.

This year's Pentagon budget, not including operations in Iraq and Afghanistan, was nearly half a trillion dollars while the State Department budget request was $36 billion -- less than his department spends on health care, Gates said.

'There is a need for a dramatic increase in spending on the civilian instruments of national security,' he said.

Gates backs Secretary of State Condoleezza Rice's request for more State Department funding and an expansion of the US foreign service. 'The need is real,' he said.

In future conflicts, 'success will be less a matter of imposing one's will and more a function of shaping behavior -- of friends, adversaries, and most importantly, the people in between,' Gates said.

Therefore, the US must get better at integrating the work of troops and civilians, communicating its values, training the armed forces of other countries and helping unstable nations build the rule of law.

Gates, who replaced Donald Rumsfeld at the Pentagon last December, bemoaned the budget cuts suffered by the State Department and the US Agency for International Development in the years following the end of the Cold War.

He said Democrats and Republicans, both in the White House and Congress, shared the blame.

President George W Bush's Republican administration has been widely accused of relying too much on military might and not enough on diplomacy to conduct foreign policy.

Gates said funding for non-military foreign affairs programmes had increased since Bush took office in 2001 but was 'disproportionately small' compared to military spending. Reuters