Hashmat Karzai, cousin of Afghan President Hamid Karzai, speaks during a news conference in Kandahar in March. (Ahmad Nadeem/Reuters)

Afghan President Hamid Karzai’s cousin was killed at his residence by a suicide bomber Tuesday in Afghanistan’s southern Kandahar province, officials said.

The bomber, a 16-year-old boy, detonated explosives hidden in his turban while embracing Hashmat Khalil Karzai as part of special greetings for the Eid al-Fitr Muslim holiday at Karzai’s home in the Karz district of Kandahar, they said.

Hashmat Karzai, 44, a prominent candidate for the Kandahar provincial council, was at times a critic of Hamid Karzai and an ally of presidential candidate Ashraf Ghani.

For years, he ran the Asia Security Group, a company supplying logistics and protection for convoys of U.S. and other foreign troops.

“The bomber had hidden explosives in his turban and detonated them as he hugged Hashmat Khalil Karzai, as a result of which Hashmat Khalil Karzai was martyred,” the Kandahar governor’s office said in a statement.

Afghan policemen stand guard near the house ofHashmat Karzai, the cousin of Afghan President Hamid Karzai, at the site of a suicide attack in Kandahar on Tuesday. (Ahmad Nadeem /Reuters)

One other person was hurt in the attack, it said, without identifying that person or the attacker. No group asserted responsibility for the bombing, which comes amid a renewed phase of bloody attacks by Taliban militants in Kandahar and neighboring Helmand province in recent weeks.

Hashmat Karzai moved to the United States after his father was killed in the early 1980s by a relative, the New York Times reported in 2009.

He settled in Silver Spring, Md., worked at a used-car dealership and became a U.S. citizen, according to Abdul Qayum Karzai, a Baltimore resident who is Hamid Karzai’s brother and Hashmat Karzai’s cousin. Hashmat Karzai’s wife, Awista, and four children live in Dubai but were in Afghanistan for Eid, Abdul Qayum Karzai told The Washington Post. He said he heard about the killing at 2 a.m. Tuesday Eastern time.

“The armed opposition is looking for any kind of publicity and news they can create to prove their presence” and spread “chaos and disorder,” Abdul Qayum Karzai said.

Insurgents have carried out similar attacks in recent years against prominent politicians and officials. Former president Burhanuddin Rabbani, who headed a peace council formed to initiate talks with the insurgents, was killed at his residence in Kabul in September 2011 by a bomber who also had hidden explosives in his turban.

Hashmat Karzai was known to be a keen hunter who kept wild animals, including a lion, at his sprawling high-walled residence.

The attack was the latest to claim the life of a close relative of President Karzai. In July 2011, Ahmed Wali Karzai, a half-brother of Hamid Karzai, was fatally shot at his house by one of his bodyguards. The assailant was then killed by other bodyguards, and his body was later hanged by Karzai loyalists at a bazaar for public viewing.

In recent years, there have been reports of differences and disputes among various members of President Karzai’s family.

“As other Afghans are killed every day by terrorist attacks in the country, our family is not an exception, and we accept this sacrifice,” the presidential palace quoted Karzai as saying in a statement.

Ghani condemned the killing on his Twitter account.

“We will not succumb to cowardly acts of the enemies of Afghanistan,” he wrote. “Every loss of Afghans reminds us that we must stay united to overcome the challenges.” Ghani, a former finance minister, is locked in a dispute with former foreign minister Abdullah Abdullah over a recount of a presidential runoff vote in June.

U.S. Ambassador James B. Cunningham condemned the assassination, saying in a statement: “The perpetrators of the attack must be apprehended and brought to justice. The U.S. stands with the Afghan people to advance their right to freedom and prosperity.”

Aminullah Habibi, an adviser to Abdullah and a friend of the Karzai family, said: “There have been a lot of attacks recently — the police chief in Kandahar and various government buildings. . . . This is a critical time because of the issues with the election. So this might continue — the targeting of key people to threaten the stability of the country.”

Ghani and Abdullah say the runoff was marred by fraud. Amid increasing tension in the country, the United States has attempted to mediate the dispute, which is jeopardizing an election billed as the first peaceful transition of power in Afghan history.

The United Nations has sent a team of observers to oversee the audit of the votes. But the recount also has been plagued by squabbling. The new president was scheduled to be sworn in next month.

Further delays could complicate long-awaited plans for an agreement to keep about 10,000 U.S. troops in the country after international combat forces leave at the end of the year.

Abby Phillip in Washington contributed to this report.