Former prime minister Dr Mahathir Mohamad was admitted to Langkawi Hospital this afternoon after complaining of breathing difficulties.

According to his aide Sufi Yusuf, he has been placed under observation in the intensive care unit.

"He complained of breathing difficulties and was taken to the hospital. The doctors decided to put him under observation," Sufi told malaysiakini .

He said Mahathir, 81, was admitted at about 3.50pm and is conscious and stable.

"He had a free programme today in Langkawi and was scheduled to return to Kuala Lumpur tomorrow," he said.

However, he said Mahathir had kept up a hectic schedule of functions in Bukit Merah and Taiping since Thursday.

On Sunday, he delivered the keynote address at a colloquium entitled 'Internationalising the Malays', organised by the Umno Youth international relations bureau in Taiping.

Conscious and alert

Mahathir's 42-year-old son Mukhriz Mahathir told reporters outside the hospital that his father was "conscious and his condition was stable."

"He asked for some water to drink. Doctors have given him some oxygen and sedatives to make him rest. This has stabilised his condition," he said.

Mukhriz said the family hoped all Malaysians would pray for his father's speedy recovery.

Mukhriz said it was not clear how long Mahathir will be in hospital but "we are optimistic he will be able to recover from this episode," adding doctors had told him that the difficulty in breathing, could be due to his previous (heart) condition.

"He was admitted to hospital at 4.15pm complaining of breathing difficulties," the state health chief said in a statement earlier.

"He was given treatment in the emergency department and then transferred to the ICU (intensive care unit) to be treated by the specialist," Hasnah said.

Mahathir is being accompanied by his wife Siti Hasmah Mohamed Ali.

Supporters at hospital

News of him being hospitalised spread rapidly in this tiny resort island, which led to Mahathir's friends crowding the hospital floor where he was admitted.

Scores of supporters also turned up at the hospital grounds.

A long-time friend of Mahathir, Bakar Abdul Hamid, 83, said he felt sad after hearing news that Mahathir was ill and immediately rushed to the hospital.

"Tonight I will pray to Allah for his speedy recovery. I have known him for a very long time, he is a good leader and has brought a lot of development to Langkawi island," Bakar told AFP .

Langkawi received an economic boost when Mahathir initiated development during his tenure as prime minister, and promoted the island as a tourist destination.

Friends of Mahathir said that he had planned to go horse-riding with them on Tuesday.

Mild stroke

Mahathir suffered a mild stroke in November last year, caused by a clot that restricted blood flow in one of his arteries, but subsequently recovered.

He also suffered a heart attack in 1989 and had bypass surgery.

Mahathir retired from office in 2003 after 22 years in power, handing over the reins to Abdullah Ahmad Badawi, whom he has since accused of nepotism and corruption.

Abdullah and his Singaporean counterpart, Lee Hsien Loong, arrived in Langkawi on Monday for informal talks aimed at enhancing ties.