By Abdullah Hai Kakar
BBC Urdu service, Peshawar
Suicide bombers targeting Afghanistan may be recruited from Pakistan, a Pakistani government minister has said.
Suicide bombings have become increasingly common in Afghanistan
Interior Minister Hamid Nawaz told the BBC Urdu Service that the possibility of Pakistani suicide bombers crossing over the border "cannot be discounted".
The statement is a rare admission by the government that its citizens may be involved in attacks in Afghanistan.
A Taleban spokesman told the BBC that about 140 such bombers had struck in Afghanistan over the past two years.
Afghan officials often allege that the Taleban in Afghanistan recruits suicide bombers mainly from Pakistan.
Mr Nawaz said that the reason many suicide bombers originated from Pakistan was because mujahideen training camps were located in the country's tribal areas during the war against the Soviet occupation of the country from 1979.
Many Pakistani militants are sympathetic to al-Qaeda and the Taleban
He said that was especially the case in North West Frontier Province (NWFP).
A Taleban spokesman told the BBC that many Pakistani suicide bombers were recruited from NWFP or Pakistan's tribal regions to hit targets in Afghanistan.
The spokesman also said that at least 40 came from the Pakistani province of Punjab.
"All of them came from jihadi organisations," he told the BBC.
Mr Nawaz disputed the Taleban claim that 140 Pakistani nationals had been involved in such attacks over the last 24 months.
"The actual figure is much lower," he said.
Pakistan says it is tightening security on the Afghan border
A UN report released in September said that at least half of Afghanistan's suicide bombers were of foreign origin.
The report claimed that 80% of the suicide bombings in Afghanistan were planned from Pakistan.
One alleged Pakistani would-be suicide bomber was pardoned by Afghan President Hamid Karzai after he was captured.
"The government is trying to eliminate the root causes of such acts," Mr Nawaz said.
"We are trying to locate their hideouts... where such activities are planned.
"Whenever we get information about them, we crack down on them and arrest them."
Last year there was a large rise in suicide bombings, both in Pakistan and Afghanistan.
In Pakistan, over 50 such attacks claimed about 800 lives.