Some believe the bomber was backed by Pakistan
"Foreigners" were behind Monday's devastating bomb attack on the Indian embassy in Kabul, a spokesman for Afghan President Hamid Karzai has said.
Humayun Hamidzada did not name Pakistan's intelligence agency - frequently accused by Afghan officials - but he strongly implicated them.
Earlier Pakistan denied involvement in the bombing, which killed 41 people.
The Taleban have denied carrying out the attack, the deadliest in Kabul since their overthrow in 2001.
Mr Hamidzada said it was "pretty obvious" who was behind the attack. He said it had been designed outside Afghanistan and exported to it.
RECENT ATTACKS IN KABUL
April 2008: Gun attack on parade attended by President Karzai
March 2008: Six people die in car bomb attack on coalition convoy
Jan 2008: Six people killed in Taleban attack on Serena hotel
Dec 2007: At least 13 people killed in a suicide car bombing
Sept 2007: Suicide bomb attack on bus kills 30 Afghan soldiers
June 2007: Bomb attack on Afghan police bus kills up to 35 people
"The sophistication of this attack and the kind of material that was used in it and the specific targeting, everything has the hallmark of a particular intelligence agency that has conducted similar terrorist acts inside Afghanistan in the past.
"We have sufficient evidence to say that," Mr Hamidzada said.
The Afghan government has accused Pakistani agents of being behind an April assassination attempt against President Karzai, in addition to playing a role in a mass jailbreak in Kandahar last month and a string of other attacks.
Five embassy staff - India's defence attache, another diplomat, two security guards and an Afghan employee - were among those killed in Monday's bombing. More than 141 were injured.
Pakistani Prime Minister Yousuf Raza Gilani denied his country was involved in the blast.
"Why should Pakistan destabilise Afghanistan? It is in our interest, a stable Afghanistan. We want stability in the region," he told reporters on the sidelines of a meeting in Malaysia's capital, Kuala Lumpur.
A senior official at Pakistan's Inter-Services Intelligence agency (ISI) described the allegations from Afghanistan as part of a "smear campaign" against his country's forces.
Meanwhile, the Afghan parliament has strongly criticised what is says is the high level of civilian casualties following US-led air strikes.
Local officials say nearly 40 people were killed in two separate incidents over the weekend, including one that allegedly struck a wedding.
Mirwais Yasini, deputy speaker of the lower house of parliament, said that MPs were urging the government to find foreign soldiers involved and bring them to justice.
"The Afghan people cannot tolerate American forces' bombing of civilians any more," Mr Yasini said.
"We are are stuck between a rock and a hard place, between Taleban attacks and foreign forces air strikes."