In defiance of a ruling from Pakistan's Supreme Court, President Gen. Pervez Musharraf had commandos waiting at the airport on Monday to deport a bitter rival back out of the country shortly after his return after years in exile.

Former Pakistani prime minister Nawaz Sharif was arrested just hours after his arrival, charged with corruption and money-laundering, then sent away on a special flight to Saudi Arabia.

In 1999 Musharraf ousted Sharif, who was then the elected prime minister, in a bloodless coup. Musharraf then exiled Sharif in 2000 to Saudi Arabia.

Sharif returned to Pakistan on Monday in hopes of mounting a political comeback and challenging the U.S.-backed general's increasingly unpopular reign in upcoming presidential elections, The Associated Press reports.

After Sharif's plane landed there was a two-hour standoff with troops, during which he refused to hand over his passport. He eventually agreed and was escorted to the airport's VIP lounge where he was arrested and charged. He was then put aboard another airplane, and departed for Saudi Arabia.

Tariq Azim, Pakistan's deputy information minister, told the British Broadcasting Corp. that Sharif chose exile over detention and trial on the charges.

"It was a choice given to him that either he goes to a detention centre and be detained and tried, or he goes and completes his 10-year (exile) agreement that he has signed with the Saudi Government," Azim told the BBC in an interview, according to an except provided ahead of its broadcast Monday night.

"No hindrance or obstacle was placed upon his entry into Pakistan. He came here and he was given every assistance."

Sharif's exile could deepen the nation's discontent with military rule and undermine the legitimacy of upcoming presidential elections.

Clashes broke out between security forces and Sharif supporters who attempted to greet him at the airport soon after his departure.

Trucks, tractors and barbed wire were used by police to block roads leading to the airport. Officers fired tear gas and supporters of Sharif threw rocks at two locations -- one near Islamabad and a bridge on the main highway leading to the capital from the nation's northwest frontier.

A number of people were injured at both sites, AP reports.

A hardline Islamic coalition allied with Sharif vowed to join demonstrations that were planned for Tuesday.

"This is an insult to our judiciary. This is a joke played on democracy and the constitution of Pakistan," said Ameer ul-Azeem, the coalition spokesman.

Last month the court ruled authorities had no grounds to block Sharif's return.

"Musharraf has probably taken a decision to twist any law to do what he can do to stay in power. This is the politics of survival," Rasul Bakhsh Rais, a political scientist at Lahore University of Management Sciences told AP.

"He is relying on strong-arm tactics, not the law and the constitution."

While the European Union criticized the decision, the U.S. took a more neutral stance. State Department spokesman Sean McCormack acknowledged the move contradicted the court ruling but said it is still under legal review.

The decision was appealed by Sharif's party to the Supreme Court -- the latest in a series of challenges by the party since Musharraf's failed attempt to oust the court's top judge in March.

That move triggered protests and calls for democracy and civilian rule.

Before leaving for Pakistan, Sharif told reporters in London that Musharraf is "capable of doing anything."

"He could impose martial law, but if he does, he will be the first casualty because the country will not accept that, the people will not accept that and I think the rank and file of the army will not accept that,'' he said.

A senior investigator, Azhar Mahmood Qazi, from Pakistan's anti-corruption body served Sharif the arrest warrant Monday.

Qazi said Sharif's charges were linked to a sugar mill business several years ago.

He is specifically accused of laundering 1.2 billion rupees (US$21.2 million).

After landing in Saudi Arabia, Sharif was taken away in a convoy from the airport. He maintains a house and several businesses in the country.

Deportation

In London, Sharif's brother, Shahbaz Sharif, said Monday that their party is challenging the deportation.

"This will be counted as the blackest day in Pakistan's history,'' he said on Geo TV. "I do not have words to describe my grief.''

AP is reporting that former president Rafiq Tarar, a Sharif loyalist, was also arrested Monday.

At least four other senior opposition leaders have also been placed under house arrest, said officials.

They included the head of a powerful political alliance that supports Sharif, Qazi Hussain Ahmed; another hard-line Islamic lawmaker, Liaqat Baluch; the acting president of Sharif's party, Javed Hashmi; and party chairman Raja Zafarul Haq.

In Islamabad, the government defended the decision to deport Sharif, claiming it was in the "supreme interest" of the country.

"Sharif's deportation is in accordance with law and ethics," said Interior Minister Aftab Khan Sherpao.

Deportation in 2000

Sharif was exiled seven years ago after being convicted of terrorism and hijacking charges in Pakistan following Musharraf's coup.

Sharif reportedly made a deal with Musharraf at the time to stay away from the country for 10 years.

His return is seen as a challenge to a possible power-sharing deal Musharraf is trying to reach with another exiled leader, former premier Benazir Bhutto.

Bhutto is trying to have corruption charges against her dropped so that she can have a chance to become prime minister for a third time in general elections due in January 2008.

An aide of Bhutto told Reuters Monday that she would likely return in October.

With files from The Associated Press