FACTBOX-What might await exiled ex-PM in Pakistan

(Reuters) - Exiled Pakistani former prime minister Nawaz Sharif is due to arrive in the capital Islamabad on Monday after seven years of exile. He is vowing to challenge military leader President Pervez Musharraf.

Army chief Musharraf overthrew Sharif in a 1999 coup. Sharif was later given a life sentence on a hijacking charge related to his refusal to allow landing rights to an airliner carrying Musharraf, despite its being short of fuel.

Sharif was allowed to go into exile in Saudi Arabia in 2000 after the government says he agreed to stay out of the country for 10 years in a deal guaranteed by Saudi Arabia.

The Supreme Court ruled on August 23 that Sharif and his politician brother, Shahbaz, had the right to come back and the government should not stop them.

Sharif had denied any exile deal with the government but said in London on Saturday he understood the agreement was for five years' exile.

Following are scenarios of what might await Sharif when he returns:

-- He could be deported upon arrival, as his brother Shahbaz was on May 11, 2004, about 90 minutes after he flew into Lahore on a scheduled flight.

Saudi Arabian intelligence chief Muqrin bin Abdul Aziz, who on Saturday urged Sharif to honor the agreement to stay in exile for 10 years, also said Saudi Arabia would welcome Sharif if Musharraf deported him.

-- He could be arrested.

Following the Supreme Court ruling that the Sharifs had the right to come back, Attorney General Malik Abdul Qayyum said if the agreement on the 10-year exile was considered void, Nawaz Sharif could face the prison term he avoided by leaving in 2000.

An anti-corruption court has reopened three cases against Sharif at the request of the government. The complaints relate to a paper mill, a foundry and some real estate, the state news agency reported.

An anti-terrorism court on Friday ordered the arrest of Shahbaz Sharif in connection with the suspected extra-judicial killing of five Islamic militants in 1998 in Punjab, when he was chief minister of the province.

-- He could be allowed to proceed as planned.

After arriving in Islamabad, Sharif plans to travel in a procession of supporters by road to the city of Lahore, 300 km (200 miles) to the southeast. Lahore is Sharif's powerbase and the nerve centre of Pakistani politics.

Party faithful could be expected to mob his convoy as it passes through towns and his journey would likely take much longer than the usual four hours.