The arrests in Pakistan which appear to have sparked security alerts in Britain and the US followed months of work against al-Qaida suspects in the region  activity that has been urged upon the president, General Pervez Musharraf, by the Bush administration.

So far, Pakistani officials say they have arrested more than 450 al-Qaida or Taliban suspects since the Afghan regime was toppled. And they say they are holding a newly captured "high-value target"  as yet unnamed. Though Pakistan has trumpeted such work, there has been speculation about Gen Musharraf's motives.

One British observer of Pakistani affairs, who declined to be named, said the president had a remarkable knack of "producing suspects out of a hat whenever he has reasons to do so".

The arrest of Ahmed Khalfan Ghailani on July 25  days before the Democratic convention in the US  was Pakistan's biggest success since last year, when it seized Khalid Sheikh Muhammad, seen as the al-Qaida No 3. Mr Ghailani had been indicted for murder over the 1998 US embassy bombings in east Africa. America had offered up to $25m (#13.7m) reward for his capture.

Last month, The New Republic magazine quoted unnamed Pakistani security officials as saying the Bush administration had been pressing Gen Musharraf to catch Osama bin Laden, his deputy, Ayman al-Zawahiri, or the Taliban leader, Mullah Omar, before the US elections in November.

One source in the report said the White House suggested the first three days of the Democratic convention would be the best time for such arrests. The story has been strongly denied.

"The war on terror is not kid's play," a Pakistani security official told the Christian Science Monitor. "If there is a pressure, then it is the pressure on both American and Pakistani investigating agencies of eliminating the dangerous terrorist network of al-Qaida." Regardless of electoral considerations, US officials say privately they have had to constantly press Pakistan to keep up its efforts, especially in the remote and difficult tribal areas where successes have been declared prematurely.

In March, 7,000 troops besieged a mountain stronghold for almost a week while senior officials hinted Ayman al-Zawahiri might be cornered inside. He wasn't. After the siege, security forces found a series of escape tunnels.

Whatever the pressure, though, Gen Musharraf is faring quite well out of it. In May, the five-year suspension of Pakistan's Commonwealth membership  imposed when the general seized power  was lifted.

The country has also been hailed as a major non-Nato ally of both the US and Britain and it has escaped without too many questions over the role of its nuclear expert, Abdul Qadeer Khan, in giving technology to Iran, Libya and North Korea.

More importantly, Pakistan is getting money  probably far more than the $700m the US has officially earmarked. A small note in a recent national bank quarterly report showed Pakistan is getting $1bn a year for "logistical support".

A cynical view is that Pakistan has more to gain from waging a long and highly public war against terrorism than it has from totally defeating it  because the foreign aid could dry up.

But there is no doubt that Gen Musharraf genuinely opposes al-Qaida.

"We are certainly winning," the president told Dawn newspaper yesterday.

Recalling the time before he took power, when a single outlaw terrorised the Punjab and could not be caught, and when foreign militants mingled "with our own religious and sectarian extremism", he said: "Now we are acting against them, very actively. Previously nobody had the courage to do that.

"We are arresting them  we are eliminating masterminds  I will oppose them tooth and nail."

Gen Musharraf has been making long-term efforts to reduce militancy by promoting state schools but the effects will take years to filter through. This gradualist approach reflects his weakness domestically, since it would be too dangerous for him to confront religious schools directly.

The problem, says Gareth Price of the Royal Institute for International Affairs, is that he cannot implement his vision for Pakistan in the short term. "On one hand he needs to maintain US support economically, but politically he needs to maintain the support of the Islamic parties."