Pakistani police say they have arrested seven members of a group linked to al-Qaeda, who are accused of planning a series of attacks in Karachi, the country's business hub.
Suicide vests, explosives and weapons were seized in a raid on the group's hideout on Sunday night in the Defence neighbourhood of Karachi, police said.
The men, who are said to belong to the Lashkar-e-Jhangvi (LeJ), were planning to attack important government buildings and senior government officials, Fayyaz Khan, a police officer, told the Reuters news agency.
"We have recovered three suicide jackets, four AK-47 rifles, four pistols and 15kg (33lb) of explosives," he said.
Lashkar-e-Jhangvi is blamed for two failed assassination attempts against Pervez Musharraf, Pakistan's former president, and the beheading of Daniel Pearl, a Wall Street Journal reporter.
Khan said that Muhammad Shahzad, one of the detained men, had been involved in planning an attack on Musharraf, and another attack on Shaukat Aziz, the former prime minister.
The Sunni Muslim Lashkar-e-Jhangvi is one of Pakistan's several al Qaeda-linked groups that began by targeting minority Shia Muslims.
Pakistan's government has held it responsible for the lorry bombing of Islamabad's Marriott Hotel in September last year in which 55 people were killed.
Attacks in Pakistan have increased over the past several months.
At least three people were killed in a suicide bombing in the city of Peshawar in the country's northwest on Sunday.
The attacker blew himself up outside the home of a brother of Mubeen Afridi, a spokesman for the Taliban-linked group Ansar Ul Islam, who was killed a day earlier.
But officials said all the victims of the attack were innocent passers-by.
Another 15 people were wounded in the attack on the outskirts of the city.
Ansar-ul-Islam fighters operate in Khyber tribal district near the border with Afghanistan.
Ghayyur said police suspect that Lashkar-e-Islam, a rival group, could be behind Saturday's attack.
The government last year launched a major operation against groups in Khyber which sent their leaders moving into the mountains bordering Afghanistan, after the militants threatened to take over Peshawar.