islamabad: tightening the noose on pro-taliban forces in pakistan, the musharraf administration on tuesday detained three hardline muslim clerics even as islamabad was turned into a veritable fortress to pre-empt violence that saw four persons being killed elsewhere in widespread riots across the country. continuing the musharraf government's crackdown on the hardline islamic clerics, the police put under house arrest three prominent leaders in a bid to stop further demonstrations. senior jamiat ulema islami (jui) party faction leader fazlur rehman was detained in his northwestern hometown of dera ismail khan for the second time since saturday. another jui chief, samiul haq, was placed under house arrest in northwestern akora khattak, where he runs a prominent seminary and taught taliban supreme leader mullah mohammad omar in the early 1990s. azam tariq, head of the sunni extremist group sipah-i-sahaba pakistan (ssp), was detained at lahore airport overnight and restricted to his home in jhang, central punjab. spokesmen for the parties condemned the action against their leaders and threatened to intensify their agitations. the protest in the small town of kuchlak, near quetta, was the deadliest in pakistan since the start of the us bombing in afghanistan. four people, including a 13-year-old boy, were shot to death when up to 400 baton-wielding afghan refugees attacked a police station, authorities said. aggravated by the sight of us or british jets flying high overhead — apparently on their way to attack targets near the taliban stronghold of kandahar some 180 km to the northwest — the demonstrators torched a police station. the protesters were armed, and all were shot in self-defense, police officials said. quetta police chief abid ali said 75 people were arrested. in lahore, several hundred pro-taliban demonstrators stoned police, blocked roads and chanted slogans against us president bush and pakistani president musharraf for his support of the us. protesters sounded similar themes without violence in other cities — 5,000 in karachi, 2,000 in chaman and several hundred in peshawar. denouncing violence and justifying his alignment with the us, musharraf said, ''in an islamic society, there is no room for extremism and violence against any other religion or group. he said backing the us in its war against terror was part of ''supreme national interests.''