(BBC) The Obama administration has asked the US Congress for an extra $200m to help displaced people in northwest Pakistan, the top US envoy to the region says.

Richard Holbrooke said the cash was needed for emergency aid to help people affected by the anti-Taliban offensive.

Mr Holbrooke was speaking at a news conference with Pakistani President Asif Ali Zardari in Islamabad.

He said it was ludicrous to suggest that anyone but al-Qaeda and the Taliban are responsible for the crisis.

Diplomatic tightrope

The US envoy to Pakistan and Afghanistan was responding to claims in a new taped message by al-Qaeda leader Osama Bin Laden that it was US pressure which led to the army's offensive and caused millions of people to flee the Swat valley region.

Mr Holbrooke wants to focus in public on the issue of helping more than two million people displaced by the fighting between government forces and Taliban militants.

Hence the announcement of a request for significant additional funding - he said that he hopes the people of Pakistan will understand that the US has given more assistance to people affected by the fighting than the rest of the world combined.

"The United States will now have given well over half of all the assistance that your country has received from the world in regard to the refugee crisis. I must say in all frankness I think other countries can and should do more," Mr Holbrooke said.

Concentrating on the humanitarian crisis is a  deliberate strategy in a country where the United States is not popular.

Mr Holbrooke is as ever treading a diplomatic tightrope - wanting to express support for military action by Pakistan, without giving the impression that it is being done at the behest of the US.

Asif Ali Zardari, standing alongside Mr Holbrooke at the news conference, said his government was defending the homeland against a serious threat.

But he acknowledged that the fight to win hearts and minds was only just beginning.

To underline the depth of that challenge a new report from the International Crisis Group has warned that unless relief, rehabilitation and reconstruction efforts are urgently improved, the army's offensive against the Taliban risks leaving extremists as the ultimate winners.  (Morris, Chirs)