KABUL—The former United Nations envoy to Afghanistan accused Pakistan of undermining negotiations with the Taliban by arresting senior Taliban officials.

Kai Eide, a Norwegian diplomat who stepped down from the U.N. post this month, said in a British Broadcasting Corp. interview broadcast Friday that he had been engaged in negotiations about a possible end to Afghanistan's war with "senior Taliban leadership" since last spring, with the apparent blessing of the insurgency's overall chief, Mullah Muhammad Omar.

These contacts, Mr. Eide added, stopped in the past few weeks after Pakistan captured the Taliban's operations chief and effective No. 2 Mullah Abdul Ghani Baradar in Karachi and detained more than a dozen other Afghan Taliban leaders.

Pakistan's motivation, Mr. Eide suggested, was to stop independent negotiations between the Taliban and the international community, so as to ensure its own control over any future settlement—a theory that Pakistani officials have denied.

The effect of the arrests, he said, "The Pakistanis did not play the role that they should have played. I don't believe these people were arrested by coincidence," Mr. Eide told the BBC. "The effect of that in total"was certainly negative on our possibilities to continue the political process that is so necessary at this particular junction."

U.S. officials with knowledge of Mr. Eide's efforts have described them as preliminary at best, playing down the progress he says he has been making.

Mullah Baradar and other Taliban leaders may have been involved in these negotiations. Coalition officials say the talks were in no way substantive, and dispute the notion that the arrests in Pakistan somehow scuttled peace chances.

Diplomats say Mr. Eide's overtures were largely his own initiative and didn't have Washington's backing. While U.S. officials endorse the Afghan government's push to reintegrate mid level Taliban, they disapprove of reaching out to senior leaders who maintain links to al Qaeda.

The Taliban have repeatedly declared they won't negotiate until international forces leave Afghanistan. Coalition commanders say the Taliban won't agree to any internationally acceptable settlement until the Islamist insurgency is first dealt a major setback on the battlefield.Any negotiations before the current military surge—in the Taliban's cradle, the southern provinces of Kandahar and Helmand—has had a chance to produce results would be premature, they warn.