If confirmed, Sunday's executions in Kunduz province would be the first of their kind by the Taleban in the area.

They also come a week after officials said the militants publicly flogged and executed a woman accused of adultery in northwestern Badghis province.

"The two were stoned to death in a bazaar of Dasht-e Archi district on the accusation of committing the act of adultery," said Mohammad Omar, the governor of Kunduz.

The Taleban arrested the two, who were each engaged to be married to other people, at the request of their families after they tried to elope, said district police chief Hameed Agha.

The hard-line militia, who drew international criticism for such punishments when they ruled Afghanistan from 1996 to 2001, have distanced themselves from the incident in Badghis.

A spokesman for the group said on Monday he was not aware of the Kunduz incident.

Shariah prescribes punishments such as stoning, lashing, amputation and execution. A gathering of clerics, meeting last week to discuss reconciliation with the Taleban, expressed support for such punishments, known as "hudood."

Some Afghans still refer to Taleban courts for settling disputes, viewing government bodies as corrupt or unreliable.

Despite the presence of more than 140,000 foreign troops, backed by 300,000 Afghan soldiers and police, the Taleban have managed to spread beyond their traditional strongholds in the south into formerly peaceful areas like Kunduz.

On Monday, a spokesman for NATO-led forces criticized the Taleban for carrying out what he said were acts of indiscriminate violence against ordinary Afghans. "They have increased acts of violence and repression against innocent Afghans," Brig. Gen. Josef Blotz told reporters.

"The insurgents have clearly given up winning over the population, knowing that they don't have an appealing vision for the people."

A UN report last week showed civilian casualties had risen by 31 percent over the first six months of 2010, with 1,271 killed, and that the Taleban and other insurgents were responsible for 76 percent of casualties.