London, Aug 28 - Pakistan President Asif Ali Zardari Friday met with British Prime Minister Gordon Brown to discuss counter-terrorism strategies.

A Downing Street spokesman said that security in the border area between Pakistan and Afghanistan remained a high priority for both governments.

Brown reiterated Britain's pledge to invest 665 million pounds over four years in programmes aimed at tackling 'the root causes of extremism', the spokesman said.

'The prime minister and the president agreed the need to tackle the underlying causes of extremism. The prime minister reiterated our support for Pakistani efforts and repeated the UK's commitment, 665 million pounds over four years.

'Our development programme in Pakistan is our second largest in the world; we aim to spend around half of this in the critical border areas.

'This requires a comprehensive approach including better governance, economic development such as a single financing mechanism, and when necessary appropriate military pressure.