KABUL, Afghanistan -- Hundreds of intelligence agents on Wednesday raided the hideout of militants with suspected links to an attack on President Hamid Karzai, as the Afghan capital was sucked deeper into the war against the Taliban.

One of the dead militants had supplied weapons used in Sunday's attack on Karzai, intelligence chief Amrullah Saleh told reporters.

Afghan security services are under pressure to crack militant cells after the assassination attempt, which came during a military parade in Kabul that was also attended by foreign ambassadors. The attack highlighted the president's weak grip on the country.

The U.S.-backed leader escaped injury, but a lawmaker and two other people were killed.

Saleh said Wednesday's raid on a densely populated hillside in western Kabul was part of a wider operation in which six other militant suspects were detained elsewhere in the city.

He said the border regions of neighboring Pakistan were the source of the militant threat.

Saleh alleged that militants involved in the gun and mortar assault on Karzai were exchanging cell phone text messages with people in Pakistan's Bajur and North Waziristan regions and the main northwestern Pakistani city of Peshawar.

Although he did not directly implicate Pakistan's government, Saleh's comments could dampen recently improved relations between the countries, relations often strained over allegations that Pakistan helps the Taliban.

"We have no evidence whether ... the operation has had any mercy or go-ahead from the government of Pakistan and [its] special agencies," Saleh said. "There [is] very, very strong evidence suggesting that Pakistan's soil once again has been used to inflict pain on our nation."

Pakistan army spokesman Maj. Gen. Athar Abbas called the allegation "baseless."

"Anybody can say that militants [in the tribal areas] have done this or that," he said. "How can one validate such claims?"

The Taliban has claimed responsibility for the attempt on Karzai's life.

It was at least the fourth attempt to assassinate him since he came to power six years ago. That attack exposed how despite the presence of more than 40,000 U.S. and NATO-led troops and rapidly expanding Afghan security forces, Karzai is struggling to contain the insurgency.

At least 1,000 people have died in fighting in 2008. The U.N. says more than 8,000 people, most of them militants, died in insurgency-related violence in 2007.

The Taliban, whose hard-line regime was driven from power by U.S.-led forces in late 2001, are now strongest in the volatile south and east of the country.

Kabul has often been hit by Taliban suicide bombers, but gun battles between security forces and militants are still rare in the capital.

Wednesday's operation began in the early hours. The first gunfire rang out before dawn.

Standing about 500 feet away, an Associated Press reporter watched armed agents gradually close in through the warren of homes on the hillside near the historic Babur Gardens, a popular public park.

The two sides traded assault rifle and machine-gun fire. Puffs of dust burst up from around the targeted house during the battle.

Some families evacuated their nearby homes, but most stayed as explosions reverberated and gunfire pierced the air.

The firing subsided after 8 a.m. following three big explosions -- two from rocket-propelled grenades fired by agents and a third, larger blast that apparently collapsed part of the two-story mud-brick building. By about 10 a.m., the fighting was over.

Saleh said security forces used heavier weapons fire when it was clear the militants in the house would not surrender.

"In the beginning we thought that this could be solved by a soft-knock," Saleh said. "However we found out very soon that we needed to use various types of weapons to dislodge them."

Residents emerged from their homes as calm returned.

Mohammed Ajmal, a man in his mid-20s, appeared pale and shaken.

"We kept hearing gunfire and the intelligence officials would not let us out of the house," he said. "But we knew they were firing at this one house, not at us."

Ajmal said people inside the targeted house had rented it three months ago, but he did not know them or where they came from.

"They looked like regular people and we thought they were very poor," he said.

Afghan lawmakers on Tuesday passed a vote of no-confidence against the country's three top security officials -- including Saleh -- after they revealed they had been aware of the assassination plot against Karzai but failed to stop it. The officials retained their jobs.

• Associated Press writer Amir Shah contributed to this report.