ISLAMABAD - Authorities are holding six suspects in connection with an attack that wounded Pakistan's religious affairs minister and killed his driver, officials said Thursday. Members of his inner circle were among those being questioned.

The attack has raised concern about security in the capital and the ability of Pakistani police to protect top officials.

No group has taken responsibility for Wednesday's gun assault on Hamid Saeed Kazmi, but the minister is a vocal Taliban critic and the Islamist militants are suspected. Authorities have been on alert for revenge attacks following the Aug. 5 killing of Pakistani Taliban chief Baitullah Mehsud in a CIA missile strike.

Kazmi was shot in the leg and was in stable condition, officials said.

The driver of his Toyota Corolla was killed and a guard was wounded in the attack, police said. Authorities said two gunmen on a motorbike were involved in the shooting. They struck seconds after Kazmi's vehicle left his office, witnesses said.

Top officials scrambled Thursday to allay fears of insecurity in the capital.

Islamabad police Chief Kalim Imam said police were investigating leads and expressed optimism that the gunmen would be traced soon. He would not give details of the six suspects, who he said were already in custody.

"This is a crime, and we are going to resolve it very soon," he said.

Imam defended the Islamabad police's performance, saying they had arrested 46 alleged militants in the past three months, including some who wanted to "target key installations" in the city.

Pakistani authorities frequently claim to have rounded up terror suspects, but few are known to ever reach trial.

Interior Minister Rehman Malik said two pistols, a Kalashnikov rifle and a black bag were discovered near the scene of the attack. He suggested someone in the minister's office may have given away his movements, but provided no evidence of that claim.

"In such a targeted action, attackers use all their connections," Malik said, adding that those around Kazmi were being questioned.

Malik also said Pakistan's government is trying to get more bulletproof vehicles to transport top officials.