A microbiology professor at Kabul University, a fourth-year medical student and a security guard at the presidential palace were among six people arrested in a plot to assassinate President Hamid Karzai, Afghan officials said Wednesday.

The spokesman for Afghanistan’s intelligence agency said at a news conference that the plotters had confessed to working with two men, an Egyptian and a Bangladeshi operating out of Pakistan’s tribal region, who were allied with al-Qaeda and an insurgent group linked to the Taliban. Lutfullah Mashal said the “dangerous and educated group” planned to have the security guard kill Karzai on one of his trips to the provinces.

The arrests drew attention again to the danger facing top government officials here. In recent months, assassins have killed several key figures, including the president’s half brother, Ahmed Wali Karzai, head of the Kandahar provincial council and a regional power broker; leading police officials; and the mayor of Kandahar city. Last month, a man with a bomb in his turban killed former Afghan president Burhanuddin Rabbani, who was leading the government’s efforts at peace talks.

The head of the alleged six-man cell was identified as Emal Habib, the chairman of the microbiology department at Kabul University’s medical school. Afghan authorities said Habib worked with three university students who lived in Kabul, as well as with Mohibullah Ahmady, a guard with the palace administrative department, who was from Karzai’s home village of Karz, on the outskirts of Kandahar. They did not give details about the sixth man arrested.

The plot allegedly began a year ago when Habib made contact with people in Pakistan affiliated with terrorist groups. Afghan authorities said Habib and others visited the northwestern city of Peshawar and later the nearby tribal region of South Waziristan, where they met with two men, identified as Egyptian and Bangladeshi, who were affiliated with al-Qaeda and the Haqqani network, an insurgent group active in Afghanistan that has ties with Pakistan’s intelligence service. The group spent a week living in a mosque and learned how to fire guns and make bombs, according to Afghan officials, who added that $150,000 was paid into Habib’s Kabul Bank account by unspecified international organizations.

A professor, three university students and a presidential guard were among six arrested in an alleged plot to kill Afghan President Hamid Karzai. (Kamran Jebreili/AP)

Karzai has survived assassination attempts in the past. In 2002, a gunman in an army uniform opened fire, but missed, while the president was traveling in Kandahar city. In 2008, insurgents attacked while Karzai was attending a military parade in Kabul. He has also had close calls from rocket attacks.

The persistent threat has prevented Karzai from traveling widely in the country, and he lives surrounded by guards, checkpoints and towering walls. The presidential security force includes more than 1,000 people, many of them loyalists from Karzai’s Pashtun tribe and home town. But his advisers worry that no security measure can prevent one of his guards from turning on him.

Mashal did not say when the six men were arrested, but a colleague of Habib’s said he had been absent from the university for about two weeks.

The dean of Kabul University’s medical school, Shirin Agha Zareef, said Habib had worked in the department for seven or eight years, spoke fluent English and “was very intelligent and very punctual in his classes.” The one development that captured Zareef’s attention was that Habib grew a long black beard and began to disregard the faculty’s Western-style dress code in favor of the traditional Afghan baggy pants and tunic.

When he confronted Habib, he said, he was told: “Mr. Dean, I have a pain at my waist. That’s why I can’t fasten a belt.”

“There are 260 professors,” Zareef said. “It’s difficult to know each one well.”

Hamdard is a special correspondent.