Pakistani authorities deported the exiled head of a key opposition party, about 90 minutes after his return to the country. Shortly after arriving Tuesday by plane from London, opposition leader Shahbaz Sharif was forced onto a second aircraft bound for Saudi Arabia.

Mr. Sharif is the brother of Nawaz Sharif, who served as prime minister until being ousted in bloodless military coup by Pakistan's current president, General Pervez Musharraf. Both brothers fled the country following the 1999 coup.

Information Minister Sheikh Rasheed Ahmed told reporters following Mr. Sharif's departure, that his attempt to visit Pakistan violated a promise made by him and his brother to remain in exile until 2009.

Government officials say Saudi authorities will likely prohibit Mr. Sharif from attempting another trip to Pakistan.

Mr. Sharif's party, the "Nawaz faction" of the Pakistan Muslim League or "PMLN", denies the existence of any such agreement.

Before leaving Britain, where he had spent the last year seeking medical treatment, Mr. Sharif said he wanted to come to Pakistan to dispute criminal charges against him. He stands accused of ordering police to kill a group of activists during his brother's administration, a charge that his party says was politically motivated.

The party also says hundreds of PMLN activists were detained during the past several days in order to prevent them from staging a demonstration in support of Mr. Sharif's return.

The government has said the detentions were made under a threat to public order.

A top PMLN official, Ehsan Iqbal, says President Musharraf believes he can silence the opposition because of his alliance with western powers in the global war against terrorism.

"General Musharraf is not ruling with the support of the people of Pakistan," he said. "He tells his people that he has unqualified support from the West and the United States, and he is free to do whatever he wishes to the democracy ? in this country."

PMLN leaders also accuse the government of issuing a security alert at Pakistani airports in order to prevent Mr. Sharif's supporters from meeting him upon his arrival. Pakistan's Prime Minister Zafarullah Jamali said earlier that the alert was connected to information about a possible hijacking plot.