President Hamid Karzai announced Tuesday details of the first stage of a plan to give Afghan forces more authority in security matters, saying that his countrymen understand “it is their responsibility to protect this soil.”

Under the plan, in July, Afghan forces will assume the nominal lead for ensuring the security of three relatively stable provinces and four cities.

The beginning of the handover will coincide with the scheduled start of the U.S. military pullout, which commanders have said will be slow and gradual.

The Afghan government and NATO officials say they want the transition to be complete by the end of 2014, when the Obama administration hopes the United States will end its combat mission in Afghanistan.

The transition is taking place at a time of deepening concern about the toll the 10-year-old war is taking on civilians and amid uncertainty about the prospect of negotiating a truce with the Taliban and other armed groups.

The government intends to assume formal control first over the northern provinces of Panjshir and Bamian. Both have remained relatively safe in recent years, even as security has deteriorated sharply elsewhere in the country.

Karzai said Afghan authorities will take primary responsibility this summer for security in Lashkar Gah, the capital of volatile Helmand province, in the south; Herat, the capital of a western province of the same name; Mazar-e Sharif, the capital of the northern province of Balkh; and Mehterlam, the capital of Laghman province in the east.

Karzai also named Kabul province, which includes the nation’s capital, as one of the areas to be subject to transition, even though it has long been under Afghan control.

NATO and Afghan officials worry that the transition plan could turn the designated areas into targets as insurgents seek to undermine the government’s attempt to show it is ready to assume more control. Those concerns stem partly from the example of Iraq, where provinces handed over to Iraqi control came under attack.

The president used his speech, delivered at the National Military Academy of Afghanistan in Kabul, to urge insurgents to lay down their arms.

Addressing the Taliban, Karzai said, “There is a place for those who are willing to live in peace and brotherhood.”

The president said he understood and acknowledged the grievances that have emboldened the insurgency. “We know that not all of the people who have taken up arms against their country are terrorists,” Karzai said.

Among the grievances he listed were airstrikes and night raids by NATO troops — tactics he has increasingly criticized. Karzai also addressed the government’s shortcomings, including the country’s broken justice system.

But he added: “Whatever the reason, we must end the bloodshed.”

In a statement Tuesday, Secretary of State Hillary Rodham Clinton said Karzai’s announcement advanced the vision reaffirmed by President Obama in a December policy review.

“As transition proceeds and Afghan leadership strengthens across the country, a process of political reconciliation to end the conflict will become increasingly viable,” she said.

NATO’s secretary general, Anders Fogh Rasmussen, also welcomed Karzai’s speech, saying the plan “represents the next stage of Afghanistan’s journey, not the destination.”

Rasmussen said he understood that as the transition begins, NATO members with a military presence in Afghanistan would feel pressure to bring troops home.

“No one wants our forces to be in combat a day longer than necessary,” Rasmussen said in a statement. “But it is vital that we maintain solidarity and continuity in order to ensure that transition is irreversible.”

Karzai’s speech included none of the jabs at the United States that have become routine in recent months as the president questioned the way the U.S.-led coalition is waging the war.

But he criticized the U.N. mission in Afghanistan, calling the administration of some of the organization’s programs “questionable.” The relationship between Karzai and the United Nations became strained after parliamentary elections last year, because the organization supported oversight electoral bodies that were at odds with Karzai.

Special correspondent Javed Hamdard contributed to this report.