KABUL, Afghanistan (CNN) -- Two service members with NATO's International Security Assistance Force in Afghanistan were killed Sunday, bringing the death toll among NATO troops to eight in three days.
The two died following an improvised explosive device attack in eastern Afghanistan, ISAF said.
Three others killed in the past few days are believed to be victims of so-called "green on blue" attacks, in which Afghan security forces turned their weapons on ISAF personnel.
Two of those were British troops, the British MInistry of Defense said. "Serving as part of an advisory team, the two servicemen were providing security for a meeting with local officials near patrol base Attal, in the Lashkar Gah district of Helmand province, when they were shot and killed by members of the Afghan Police Force."
The three other ISAF deaths include one service member killed in an insurgent attack, one killed by a roadside bomb, and one who died of non-combat related injuries, officials said.
Meanwhile, a key figure in the country's efforts to bring the Taliban to peace negotiations was assassinated Sunday in Kabul.
Gunmen killed Moulavi Arsala Rahmani while he was on his way to work Sunday morning, the Afghan interior ministry said.
Rahmani was a senator and Cabinet minister in the former Taliban government. In recent years, he was a senior member of the High Peace Council, established by President Hamid Karzai to ignite peace talks with the Taliban.
Authorities are searching for the attackers. The Taliban said it was not responsible for the killing.
The latest violence came as Afghanistan released a new list of areas in the country that will be handed over to Afghan authority.
The transition will take place gradually in the coming months, officials said.
The Afghan government "will now be responsible for the security of more than 75% of the Afghan population," ISAF commander Gen. John R. Allen said in a statement.
NATO Secretary-General Anders Fogh Rasmussen said once the move is implemented, "transition will have begun in every one of the 34 provinces of Afghanistan, including every provincial capital, and will cover almost two-thirds of the country's districts."
"This is thanks to the courage and determination of the Afghan people, the Afghan security forces and ISAF, and it is a result of the progress we have already made. Together, we are moving steadily closer to our shared goal: to see the Afghan forces fully in charge of their country's security by the end of 2014," Rasmussen said in a statement.
Gavin Sundwall, spokesman for the U.S. Embassy, said the announcement marks a "positive step forward in the evolution of Afghan leadership and our enduring partnership."
Kandahar city, until recently a Taliban stronghold, is among the areas being handed over to Afghan authority. The list announced Sunday is the third set of areas making the transition.
Included in the districts to be handed over, according to a statement from the Afghan government, are some of the more volatile parts of the country. Half of the insurgent stronghold Nurestan's districts will be handed over, as will all of restive Uruzgun province, where departing Australian forces are active.
Just over a third of the districts in violent Paktika province will also be handed over.
General Mohamed Zahir Azimi, spokesman for the defense ministry, said that at an upcoming NATO summit in Chicago, Afghan officials hope to get commitments from the international community for support after 2014. The country already has international commitments for $4.1 billion a year to fund the Afghan security forces until 2014, he said.
Despite the high praise for Sunday's announcements, the killings were a stark reminder that violence continues to rage.
In a recent e-mail announcing their spring offensive, called Al-Farooq, the Taliban mentioned that members of High Peace Council were among the people it would target this spring and summer.
However, Taliban spokesman Zabiullah Mujahid said in a text message Sunday that the group did not kill Rahmani.
An Afghan foreign ministry spokesman condemned "this cowardly assassination in the strongest possible terms."
"No one but the sworn enemies of peace in Afghanistan and the region would commit such a heinous act," Janan Mosazai said. "Mr. Rahmani gave his life to a cause that's the just aspiration of the Afghan people. His work will continue."
ISAF issued a statement expressing condolences to Rahmani's family.
"Rahmani, a former Taliban member, chose to make a positive contribution to his nation by turning his back on an insurgent movement that continues to be wholly detrimental to the future of Afghanistan," ISAF said. "His decision to help make the future brighter for Afghans serves as an inspiration to us all, and his contributions will be missed."
The U.S. Embassy said Rahmani was killed "by the enemies of stability and security. The High Peace Council has been working for a durable, long-term peace in Afghanistan. The United States of America will continue to stand alongside the Afghan Government and people against terrorism and to work with them on behalf of a secure and prosperous Afghanistan."