KABUL, Afghanistan -- President Hamid Karzai asserted Friday that Afghanistan is not descending into chaos and lawlessness even as police rounded up 17 people for questioning in the assassination attempt on his life.

Karzai said the attempt on his life and a bombing at a crowded market place on Thursday were "done by terrorists in an isolated manner. This means they are no longer capable of mobilizing as groups so they act as individuals."

He said Afghanistan has a "long way to go to bring total technical security to the country," and called for help from other countries.

The death toll in Thursday's bombing in Kabul rose to 30, and another 167 were injured, said Health Minister Dr. Sohaila Siddiqi. It was the deadliest act of violence since the Taliban fled the city in November after American airstrikes and bombings.

Karzai said he would be more mindful of his personal safety.

"I will not be as reckless as I am," he said.

'I will not stop'

He pledged to continue rebuilding the country despite the violence.

"I've been through this before," Karzai told reporters. "My father was assassinated ... by the Taliban, by terrorists. Did that stop me from fighting against them? ... I will not stop. I will continue."

The president returned to Kabul from Kandahar early Friday and in a show of business-as-usual met Russian Defense Minister Sergei Ivanov. They negotiated a supply of aircraft, military transport and communications equipment for Afghanistan's new national army.

It remained unclear who was behind Thursday's attacks and whether they were coordinated. Afghan officials speculated the attacks could have been orchestrated by Taliban or al-Qaida fugitives or by former Prime Minister Gulbuddin Hekmatyar, who is purportedly trying to forge a new alliance with both groups.

Officials in Kabul said at least two suspects have been detained for questioning after they were linked to the taxi carrying the bomb.

In Kandahar, Khalid Pashtoon, a spokesman for the provincial governor, said 17 people -- all security guards for the provincial government-- were being questioned in connection with the attempt on Karzai's life.

Was hired as guard

The gunman, Abdul Rahman, was hired about two weeks ago as a security guard. He was given clearance to carry a weapon near important government officials, police said.

Kandahar police chief Gen. Mohammed Akram said Rahman was from Helmand, a southern province in the country's Pashtun heartland known for Taliban sympathies. Resentment against U.S. operations aimed at ferreting out remaining Taliban fighters and the al-Qaida terrorist network has grown in Helmand.

The 22-year-old gunman was shot dead by Karzai's American bodyguards after he fired on the president's car outside the palace of Kandahar Gov. Gul Agha Sherzai.

An Afghan bodyguard for Karzai and a bystander were also killed. Sherzai was grazed in the neck by the gunman's bullet. He was treated and released Thursday from the medical unit of the U.S. air base south of the city.

Pashtoon said Rahman had been hired despite a prohibition against new guards. He said the screening process for applicants would be overhauled.

In Kabul, some residents expressed fear that Thursday's violence could signal renewed conflict in a city longing for peace. Small bombs have exploded in Kabul almost daily for several weeks, but Thursday's was the first to cause multiple casualties.

"We are not sure of the future. There has been so much destruction in Kabul in my lifetime," said Habibulluh, 37, who owns a store that sells watches and clocks near the site of Thursday's blast.

The explosion blew out windows and display cases in his store and caused more than $1,000 in damage -- a huge sum in Afghanistan.

"Maybe it will continue. This will not be the end," said Habibullah.