DARWIN, Australia -- (UPDATE 8) East Timor President Jose Ramos-Horta is on a ventilator but his condition is stable, a doctor said after his arrival in Australia for emergency treatment.

"He's ventilated but I wouldn't call it life support," Dr. Len Notaras, Royal Darwin Hospital general manager, told Agence France-Presse.

"He's in a stable condition and while he is on a ventilation system, it?s working with him...to make him more comfortable," he said, adding that Ramos-Horta would undergo a CT scan to determine what further surgery was needed.

The 58-year-old Nobel peace laureate was injured in a dawn gunbattle at his residence on the outskirts of the capital Dili in which rebel leader Alfredo Reinado was killed, said Deputy Prime Minister Jose Luis Guterres.

Gunmen also targeted the home of Prime Minister Xanana Gusmao in coordinated attacks that plunged the nation into fresh crisis following deadly unrest in 2006, which saw international forces deployed to restore calm.

"I understand that the condition of Jose Ramos-Horta is very serious but stable," said Australian Prime Minister Kevin Rudd.

After exploratory surgery at an Australian military hospital in Dili, the East Timorese leader was airlifted to the Australian city of Darwin for emergency medical treatment on his bullet wounds.

Rudd told reporters in Canberra his government would send "substantial" reinforcements to the 800-strong Australian troop contingent already deployed in East Timor alongside 1,700 UN police to help stabilize the situation.

"This government will stand resolutely with the democratically-elected government of East Timor at this time of crisis," said Rudd, adding that he would visit the impoverished nation later in the week.

United Nations Secretary General Ban Ki-moon said he was "shocked and dismayed" over the attack, urged the nation's one million people to remain calm and quickly dispatched Special Representative Atul Khare to Dili.

Two carloads of people came to Ramos-Horta's home at around 6 am (2100 GMT Sunday) and attacked him before heading to Gusmao's home about 90 minutes later, Guterres said.

A neighbor of Gusmao, Leandro Isa'ac, said "rounds of automatic fire were fired against Xanana's residence" in the foothills south of Dili, where he lives with his Australian wife Kirsty Sword and their three young sons.

Addressing a press briefing, Gusmao -- who served as East Timor's president following independence in 2002 until Ramos-Horta was elected last year -- said the situation was now under control.

"Even though the state has been attacked by an armed group and the president was wounded, the state is in control of stability... The current situation is proceeding normally and is under control," Gusmao said.

Reinado, who emerged as a key figure in the 2006 unrest that led to the deaths of at least 37 people and displaced more than 150,000 others, was shot dead at Ramos-Horta's residence, Guterres said.

"Major Reinado was killed and at the same time one of the presidential guards was injured," the deputy prime minister said, adding that security forces were hunting for more of the attackers.

New Zealand Defense Minister Phil Goff said his country's troops had helped to secure both homes following the rebel raids, and that an extra platoon was on stand-by to head to Dili if needed.

Reinado was arrested on charges of illegal weapons distribution, desertion and attempted murder related to the unrest involving factions of the military. He had however escaped from jail and eluded security forces since then.

Indonesian Foreign Minister Hassan Wirayuda said the attack "once again showed that the security situation in East Timor continues to be disturbed."

He said that with the death of Reinado, "hopefully the rebellion will weaken and it is our hope that his followers surrender so that the problem of security disturbances in this neighbor of ours can soon be overcome."

Security was tightened along the common border to prevent the rebels from escaping, Indonesian officials said.

Indonesia invaded East Timor in 1975 and ruled brutally until the United Nations took charge and the East Timorese voted overwhelmingly in favor of breaking away in 1999.

Ramos-Horta's opposition to Indonesian rule and his efforts to bring peace to his homeland earned him the 1996 Nobel Peace Prize, which he shared with Bishop Carlos Felipe Ximenes Belo.

Reinado led a ragtag bunch of rebels who were demanding that they be reinstated in the army after being sacked in 2006 following their desertion.

Most of those displaced by the violence in the streets of Dili remain in camps at night, still too concerned about the fragile security situation to return home, or with no homes to return to.

The International Crisis Group warned last month that East Timor risked descending into violence again if its government and the UN failed to quickly reform the security forces, which it said remained vulnerable to political influence.