Islamabad - All educational institutions across Pakistan remained closed on Wednesday, a day after twin suicide bombings rocked an Islamic university in the country's capital, killing eight people.

The explosions were apparently part of a string of militant attacks on civilian and official targets as government forces continue with their push into the Taliban stronghold near the Afghan border.

The suicide bombers simultaneously struck a cafeteria for women and a sharia law school in an academic block for men at the sprawling university, which also hosts foreign faculty and students.

No group has claimed responsibility for the attack but Pakistani Interior Minister Rehman Malik on Tuesday said "all roads were leading towards South Waziristan."

Initially, only the Islamic university suspended classes Tuesday but as the scare spread, regional governments ordered the closure of all educational institutions throughout the country.

The institutions are likely to reopen next week, but authorities in Pakistan's eastern Punjab province, which witnessed coordinated terrorist attacks on police buildings last week, said the institutions "will remain closed till further orders."

Schools and colleges run by the military and nationwide chains popular among the elite were closed for a week soon after ground troops launched a much-awaited offensive against the Taliban in South Waziristan on Saturday.

The lawless region is the heartland of the Pakistani Taliban leadership and contains safe havens for al-Qaeda fighters, who fled the US-led invasion of Afghanistan in late 2001.

Intelligence officials said on Wednesday that troops were engaged in fierce fighting at Kotkai, the birth place of Taliban chief Hakimullah Mehsud and also the home town of Taliban commander Qari Hussain, known as the "mentor of suicide bombers."

"There are reports of fresh casualties but we don't have the numbers," said the official, who spoke on condition of anonymity.

Major General Athar Abbas, the military's chief spokesman, said the security forces positioned on high land were engaged in "an envelopment manoeuvre" around Kotkai, which is on the route to another rebel stronghold - Sararogha.

The army says it has killed up to 90 militants and suffered 13 casualties since the start of the offensive, but the Taliban rejects the claims. Independent verification is unavailable as journalists are not allowed into the battle zone.

More than 30,000 soldiers, backed by jet aircraft, helicopter gunships and artillery, are taking on around 10,000 insurgents, with an al-Qaeda contingent of up to 1,500 men, mostly Uzbeks and Arabs.

The operation, codenamed Path to Deliverance, was launched following a string of brazen assaults on Pakistani security forces and other targets, including United Nations offices, which have killed more than 160 people since October 5.

Authorities are bracing for more violence amid new intelligence about terrorist attacks, most probably hostage situations.

Pakistani President Asif Ali Zardari has condemned the wave of terrorist strikes, vowing that, "The operation against the terrorists in Waziristan and other areas will continue till their complete elimination." (dpa)