Pakistan's commercial capital Karachi was tense on Saturday a day after two bombs killed 25 people, raising further questions about the effectiveness of security crackdowns on Al-Qaeda-linked militants.
Most shops in the sprawling city of 18 million people were closed and public transport was off the roads as several thousand mourners gathered at funerals of some of the victims of the two bombs, which wounded more than 150 people.
The first attack on Friday killed 12 Shiites, followed hours later by a blast at a hospital where the wounded were being treated which killed 13 people.
Pakistani Taliban have carried out waves of bombings at crowded markets and army and police facilities since October, killing hundreds of people in a bid to topple the pro-American government of unpopular President Asif Ali Zardari.
Al Qaeda-linked Sunni Muslim militant groups have often carried out attacks on their rivals from Pakistan's Shi'ite Muslim minority.
"It looks like there's no government in Pakistan," said Shi'ite Muslim Syed Shabbir Hussain, who lost a cousin in the first blast on Friday.
"They always say that there are militants here, and that they will attack. And then they attack, but the police and the government do nothing," he said at his cousin's funeral.
Carnage in the home of Pakistan's stock exchange and main port could further discourage investors, who have watched the Taliban spread their violent campaign from strongholds in lawless areas near the Afghan border to major cities.
The latest attacks come as the United States is pushing Pakistan to help stabilise neighbouring Afghanistan.
Police had initially suspected that the two attacks in Karachi were carried out by suicide bombers but later said the devices were planted. A third bomb, defused at the hospital, was similar in type, indicating just one group was involved.
Senior police investigator Raja Umer Khattab said the Jundullah (Army of God) militant group was behind the attacks.
"This is the same group that carried out the Ashura attack," he said, referring to a bomb attack at a Shi'ite procession in late December that killed 43 people.
Khattab said some arrests had been made after the December attack but police were hunting for more members.
"We have arrested four members of this group but there are still 12 to 14 militants of this group left, who are planning these attacks," he said.
Another militant group with the same name is fighting the Iranian government.
The attacks once again fuelled concerns that the militants were expanding their fight to the city, which already has its share of problems.
Dozens of rival political workers have been killed in violence in Karachi over recent weeks which has raised questions about the future of Zardari's coalition.