International peacekeeping commanders sought an explanation from Afghan authorities Friday for a roundup of hundreds of men who one Kabul official claimed were plotting a "coup d'etat" against the interim Afghan regime.

The peacekeepers, responsible for security in the Afghan capital, were not informed beforehand about the reasons for the massive operation by the Afghans, a spokesman for the International Security Assistance Force, or ISAF, said.

"If there was going to be some sort of coup, perhaps you should let us know about it," was how spokesman Flight Lt. Tony Marshall characterized the ISAF commanders' inquiry.

Government officials reported on Thursday that hundreds were rounded up and many released, but 160 people linked to a hard-line Afghan Islamic group were still under arrest in connection with an alleged plot to attack interim leader Hamid Karzai and "harm" and "sabotage" his government.

Offices were closed for the Muslim sabbath Friday, and no further information was available on any additional releases of detainees.

One official, Mohammed Naseer, security director at the Kabul governor's office, said Thursday the suspects "wanted to launch a coup d'etat against the government" — that is, take over Afghanistan.

The interior minister, Yunus Qanooni, said later that the group's ultimate aim remained to be determined through investigation. He told reporters that authorities had seized explosives with remote control devices and "written documents" indicating the suspects would carry out "terrorism, abductions and sabotage." He did not elaborate.

Most of those arrested were associated with the Hezb-e-Islami party of former Prime Minister Gulbuddin Hekmatyar, Afghan officials said.

Hekmatyar has been a vocal opponent Karzai and of the U.S. presence on Afghan soil, but last month his deputy, Jumma Khan Hamdard, said the party was ready to cooperate with the interim administration.

A spokesman for Hezb-e-Islami said Friday that the group had nothing to do with the alleged plot, saying the people arrested had left the group years ago.

The spokesman, Ghairat Basher, a son-in-law of Hekmatyar, said Hezb-e-Islami officials had held peaceful talks with Karzai's administration and planned to continue them in the near future.

"We are for peace in Afghanistan and for peace, we are cooperating with Hamid Karzai's government," he said by telephone from Islamabad, Pakistan.

Still, the arrests may inflame tensions between Hekmatyar's Pashtun followers and Qanooni's northern alliance, which is dominated by minority Tajiks and controls key ministries in the interim government in Kabul. Some Pashtuns — Afghanistan's largest ethnic group — may interpret the arrests as an attempt to stifle moves toward Pashtun unity in advance of the loya jirga, or national council, that meets in June to select a new government.

The 4,500-member, 18-nation security force, established by the U.N. Security Council in late December, was informed of the roundups beforehand to avoid accidental clashes between ISAF and Afghan security forces, ISAF officers said. But "the reason behind the Interim Authority's arrest operations was not a subject they wished to give to ISAF," said ISAF spokesman Lt. Col. Neal Peckham, like Marshall a British officer.

Maj. Gen. John McColl, ISAF's British commander, was leading a peacekeeper delegation meeting with Afghan officials seeking "clarification."

"If there wasn't a coup," Marshall said, "perhaps we need to talk about not using inflammatory language."

Peckham said Kabul remained quiet despite the roundups. "We have not seen any ripples in day-to-day life as a result of those arrests," he said. He also said the ISAF was not aware of any specific threats against foreigners. Afghan officials said the alleged plotters had planned such attacks.

Power struggles among Hekmatyar's forces and northern alliance factions devastated much of Kabul in the early 1990s and killed some 50,000 people, mostly civilians, according to the International Red Cross.

Hekmatyar fled to Iran after the Taliban took the capital in 1996, but the Iranian government recently closed his offices in Tehran. Basher said Friday that Hekmatyar was in Afghanistan, but he would not say where.