AHEDAN, Iran, Oct. 8 — Iran's supreme religious leader, Ayatollah Ali Khamenei, condemned the strikes on Afghanistan today as cruelty and said they would prove a major mistake for the United States and Britain.

"What can justify this oppression that will lead to the killing and wounding of people and forcing many innocent Afghans to leave their homes?" he asked at a meeting in Tehran of clerics from around the country.

The United States has said the strikes are part of its campaign against terrorism. Ayatollah Khamenei said that was not true. "Their real purpose is to expand their power and domination," he said.

"The Americans must know that they might be able to achieve their short-term goals with military strikes," he said. "But they will be hurt in the long run. Without doubt, their acts will bring instability for them."

Foreign Minister Kamal Kharazi also condemned the attacks, but in milder tones, expressing Iran's concerns that such military operations could "provoke extremist reactions."

"We stressed from the beginning that terrorism cannot be eradicated through military actions," he said at a news conference. "Its causes must be identified and eliminated."

He also said that Iran had asked Washington not to violate its airspace or use its territory against Afghanistan and that the United States had agreed.

Iran is officially a Shiite country and criticizes the extreme interpretation of Islam by the Taliban as backward and dangerous. Iran nearly went to war with Afghanistan three years ago, when the Taliban killed 11 Iranian diplomats and a journalist.

Despite the official denunciations of the military strikes against Afghanistan, some people in Iran said they believed that the situation offered an opportunity to mend relations with the United States.

Washington broke diplomatic relations with Iran in 1980, months after militants in the new Islamic republic had taken dozens of American diplomats hostage. The State Department has listed Iran as a country that sponsors terrorism.

But here in Zahedan, the provincial capital of Sistan-Baluchestan, in part because of its proximity to Afghanistan — 20 miles away — and common religious and tribal factors, there was little support for the military operations.

Golmohammad Yassin, a government worker, said that although he did not have anti-American feelings, he was glad that Ayatollah Khamenei had ruled out cooperation with the United States against "Muslim brothers" in Afghanistan.

Some Afghans in exile here doubt that the military campaign will bring peace and stability to their country devastated by drought and decades of civil war.

Abdolrahman Arabzadeh, deputy director of the Office for Assistance to Afghan Refugees in Zahedan and a member of the exiled Afghan opposition for years, said the attacks would create further misery for the Afghan people. "To kill five of the Taliban militias, they will kill 95 civilians," Mr. Arabzadeh said. "We do not believe that America's policies would serve Afghanistan's interests."

A 32-year-old refugee from Afghanistan who gave her name as Nessa said she was so upset by the attacks that she did not go to work. She said she was determined to return and be with other Afghans.

"What is the difference between this attack and the one in the United States?" she asked. "Both killed innocent people."