Islamabad: Pakistan on Thursday alleged that India and Afghanistan were behind last month's suicide attack on a shuttle bus in the country's restive Khyber Pakhtunkhwa province that killed 13 people, including nine Chinese engineers.

The bomb attack took place in the Dasu area of Upper Kohistan district where a Chinese company is building a 4,300-megawatt hydropower project on the Indus river.

At least 13 people were killed when the bus carrying Chinese engineers and workers to the site of the under-construction Dasu Dam exploded on July 14. The bus fell into a deep ravine after the explosion.

Addressing a press conference in Islamabad after the completion of the probe, also assisted by Chinese experts, Pakistan Foreign Minister Shah Mahmood Qureshi said Afghan soil was used and the vehicle used for the attack was smuggled from Afghanistan.

He accused the Indian spy agency Research and Analysis Wing (RAW) and Afghanistan's National Directorate of Security (NDS) of carrying out the attack.

"It was a blind case but Pakistani institutions managed to trace it," Qureshi said, alleging that there is a nexus of the two agencies which were behind the incident.

He said the Pakistani authorities examined footage of 36 CCTV cameras while the area under the investigation was almost 1,400 kilometres.

Last month, Pakistan alleged that the mastermind of an attack near the residence of banned Jamat-ud-Dawa outfit chief Hafiz Saeed in Lahore on June 23 was “an Indian citizen" and he was associated with R&AW. Later it claimed that a "common link" has been established between the Dasu blast and the explosion outside Saeed’s house.

India has previously trashed as "baseless propaganda" Pakistan's claim that it was behind some attacks in Karachi and Lahore and asked Islamabad to take "credible and verifiable" action against terrorism emanating from its soil instead.

Ministry of External Affairs (MEA) Spokesperson Arindam Bagchi last month asked Pakistan to focus on setting its own house in order in containing terror networks and said that the international community is well aware of that country's credentials when it comes to terrorism.

"It is not new for Pakistan to engage in baseless propaganda against India. Pakistan would do well to expend the same effort in setting its own house in order and taking credible and verifiable action against terrorism emanating from its soil and terrorists who have found safe sanctuaries there," Bagchi said on July 8 in New Delhi at an MEA briefing.

"The international community is well aware of Pakistan's credentials when it comes to terrorism. This is acknowledged by none other than its own leadership, which continues to glorify terrorists like Osama Bin Laden as 'martyrs'," he said.

On Thursday, Qureshi claimed that the first target was the Diamer-Bhasha dam site in Gilgit-Baltistan but on failing to target it, the terrorists targeted the Dasu project.

He said the authorities have traced the handlers and the people connected with it.

The Chinese officials have visited the crime scene and were updated about the investigation, Qureshi said, adding that China was satisfied with the probe.

Director-General of Counter-Terrorism Department (CTD) Khyber-Pakhtunkhwa Javed Iqbal, who also briefed the media on the occasion, said that it was a suicide attack and a thumb and a limb of the attacker were found at the scene.

He said the suicide bomber was identified as Khalid aka Sheikh and he was an Afghan national.

Iqbal said 14 people were involved in the attack, and the group was led by a person named Tariq, a member of the banned Tehreek-e-Taliban Pakistan (TTP).

He claimed that Tariq and another person Muawiya were trained by NDS and R&AW for this attack.

"We have so far arrested three suspects and are going to nab others,” he said.

Separately, the Foreign Office said that the Pakistani authorities have conducted thorough investigations of the incident and shared the findings with the Chinese side at every stage.

The planning for the terrorist attack was done in Afghanistan, with provision of material support as well, including the vehicle, while the suicide bomber was trained in Afghanistan and brought to Pakistan to carry out the attack, it claimed.

"Some of those involved in the attack have been arrested, while others are at large in Afghanistan. An MLA (Mutual Legal Assistance) request is being made to the Afghanistan Government,” the FO said in a statement.

"We would not allow any hostile force to undermine the iron-clad friendship between Pakistan and China," it said.

Pakistan had initially said that the accident was caused due to technical problems and later an explosion occurred due to gas leakage, while China has from the beginning called it a terrorist attack due to which the vehicle fell down. Beijing also sent a 15-member team of experts to Pakistan to probe the incident.

The Dasu bus blast had accentuated Beijing’s concerns as thousands of Chinese personnel are working on the USD 60 billion China-Pakistan installations, projects and personnel in Pakistan.

For Pakistan, ties with China are crucial due to its increasing economic dependence on Beijing.

This year, the two nations are celebrating the 70th anniversary of the establishment of diplomatic relations and more than 100 celebratory events have been planned of which over 60 events have already been held so far.