President Jose Ramos-Horta was shot twice outside his home by suspected rebel soldiers last week.

Prime Minister Xanana Gusmao escaped unhurt from a separate attack an hour later.

'Information available to me says that four people have been arrested and that number could change,' said Acting President Fernando 'Lasama' de Araujo.

He gave no more details.

Attorney-General Longuinhos Monteiro said a 38-year-old woman identified as Angelita Pires was detained Sunday in the capital, Dili.

He said Alfred Reinado - a rebel leader shot by guards during the attack on Ramos-Horta - and his accomplices had spent the night at her house before the attacks.

'Pires knew that Alfredo Reinado was staying in her house,' he said. 'Why did she not tell authorities?'

He said Pires was an 'adviser' to Reinado, but gave no more details.

Pires has not been charged with a crime. Her lawyers were not immediately available for comment.

Meanwhile, Mr Ramos-Horta was making steady progress in a hospital in the northern Australian city of Darwin where he was being treated for gunshot wounds to his upper body, a spokesman said.

'The family and staff of the president are very pleased with the way things are going. He is doing very well,' Mr Luke Gosling, an official with the president's office, said in a statement.

Nobel Peace Prize laureate Ramos-Horta, who was shot outside his home in Dili on Feb 11, was sedated and scheduled for a fifth operation on Tuesday, Mr Gosling said.

Ramos-Horta and Gusmao, revered icons of resistance during 24 years of Indonesian occupation, became president and prime minister in elections last year.

The attack last week by rebels was a sudden escalation in a bitter dispute between the government and several hundred ex-soldiers who were fired in 2006 after going on strike to protest alleged discrimination.

Gusmao declared a 12-day state of emergency after the assassination attempts. -- AP