A recent increase in US drone attacks in Pakistan is linked to a suspected al-Qaeda plot to attack European targets, Pakistan's US envoy says.
Hussein Haqqani also confirmed that five Germans were among eight militants killed in a strike on Monday.
The BBC's Newsnight programme has learnt a British man killed in a strike last month was to head an al-Qaeda faction in the UK.
On Wednesday, a suspected US drone attack killed at least four people.
Local officials said the plane fired two missiles into a militant compound in Miranshah, the main town in the North Waziristan tribal district.
Speaking before the latest strike, Mr Haqqani told the BBC that the activity in North Waziristan "is connected to the terrorist warnings that we have heard about potential strikes in Europe".
Mr Haqqani said Pakistan was working with European and US intelligence agencies to prevent the suspected plans to attack Europe, and that people should not panic.
Security sources say a German man detained in Afghanistan in July had provided the first information about plans to launch commando-style attacks on targets in Britain, France and Germany.
As well as Paris and London, Berlin was cited in a US warning at the weekend as a possible target for a suspected al-Qaeda plot.
Several countries have issued travel warnings to their citizens, saying they should be vigilant while travelling in Europe.
The US has carried out 26 drone strikes on Pakistan in the past month - the highest monthly total for the past six years.
Monday's attack destroyed the house of a tribal leader with close links to a local Taliban commander in a village 3km (2 miles) from North Waziristan's main town of Mir Ali.
Pakistani officials have said five German nationals were killed along with three other militants. A number of people were said to have been wounded.
Identification of the victims is being made more difficult because Taliban militants sealed off the area after the missile strike, taking away the remains for burial.
There have been concerns about the presence of German nationals in Pakistan's tribal areas.
According to German media, several Islamist militants disappeared from their homes in Hamburg in 2009 and were thought to have headed for North Waziristan.
On Monday, the German interior ministry revealed that 70 Germans had been given paramilitary training in Afghanistan and Pakistan, and a third of them had returned home.
In August, German police shut down a mosque in Hamburg which had been used by the 9/11 attackers and which the authorities believed was again becoming a focus for extremists.
Al-Qaeda in the UK?
The area around Mir Ali has been known to harbour militants from a number of foreign countries in the past.
A drone strike in North Waziristan earlier in September killed a British national named Abdul Jabbar who had been living in Punjab province.
A British security source told the BBC's Newsnight programme Jabbar was being groomed to head an al-Qaeda offshoot in the UK.
Intelligence agencies monitored a meeting of 300 militants in North Waziristan he attended three months ago where he was put forward as the leader of the new group, which was tasked with preparing commando-style attacks against targets in Britain, France and Germany, Newsnight has learnt.
British government officials declined to comment on the Newsnight report.