Afghanistan's intelligence chief Asadullah Khalid and the country's current intelligence chief speaks to media after he survived a 2007 suicide attack in Kandahar, south of Kabul. Khalid was wounded Thursday in an assassination attempt in Kabul, Afghan officials said. (Allauddin Khan/AP)

Afghan President Hamid Karzai charged Saturday that the suicide bomber who tried to kill his top intelligence aide in the Afghan capital on Thursday had come from next-door Pakistan and that the assassination plot had been “designed” there.

Speaking with journalists at the presidential palace in Kabul, Karzai said Asadullah Khalid, head of the National Directorate of Security, was expected to “recover completely” and return to work. Khalid was severely injured in the bombing and flown to Bagram air base, the main U.S. military base in Afghanistan, for medical treatment.

Although Karzai vowed that the “peace process will continue,” the attack marked a severe setback to Afghan and U.S. hopes for progress on long-stalled peace talks with the Islamist insurgents. Karzai’s allegations of Pakistani involvement seemed likely to undermine recent positive steps in the contentious relationship between the neighboring Muslim countries.

Karzai stopped short of accusing Pakistan’s intelligence agency of planning the attack, but he described it as a “very sophisticated and complicated act by a professional intelligence service” and said his government would be “seeking a lot of clarifications from Pakistan” about the incident.

He said he was certain the bomber had come from Pakistan. “We know it as a fact,” he said. He did not offer any details or evidence to support his statements. He and other Afghan officials have often accused Pakistan’s military and intelligence services of working against Afghan interests and fomenting violence inside Afghanistan.

Pakistan has officially said it supports the peace process, and recently it released a number of Taliban prisoners as a goodwill gesture after an Afghan peace committee visited Islamabad. But Pakistan’s military and intelligence services have continued to maintain relations with Taliban leaders, apparently hedging their bets in case the Islamist militia returns to power. Some Taliban leaders are widely believed to live freely in Pakistan’s border regions.

Afghan intelligence officials said the bomber, thought to be a peace messenger from the Taliban, was invited to a guest house used by Khalid in Kabul and blew himself up as he greeted the intelligence chief. They said he had explosives hidden in his underwear, but Karzai said he was not searched because of Khalid’s “respect for our traditions and hospitality.”

An almost identical scenario resulted in the death of former Afghan president Burhanuddin Rabbani in September 2011. In that case, another ostensible peace emissary from the Taliban entered Rabbani’s house in Kabul and was not searched. Upon greeting the former president, the man detonated a bomb in his turban.

At the time, Afghan officials suggested more directly that Pakistan’s intelligence service was behind the attack on Rabbani, who was then heading a national peace council promoting negotiations with the Taliban.

Spokesmen for the Afghan Taliban claimed responsibility for Thursday’s attack on Khalid, but Karzai said that “more professional hands” were behind it. He suggested the bombing was a professional plot by an intelligence service “in our neighborhood, or somewhere else.”

The Afghan president had appointed Khalid to several senior posts including two governorships before making him his spy chief in September. Karzai said his national security adviser and defense minister had visited Khalid at Bagram on Friday and reported that he was able to talk and move his hands. Officials said the bomb caused multiple wounds to his lower body.

Khalid, 43, is a controversial figure who has been accused by international human rights groups and diplomats of running a secret dungeon and being involved in drug trafficking. However, he is also known as a tough anti-Taliban leader and is one of Karzai’s most durable political associates.

Javed Hamdard in Kabul contributed to this report.