A top official in the Maldives said Saturday that Islamic extremists were responsible for an explosion earlier this week that critically wounded former President Mohamed Nasheed, as police said they arrested two of four suspects.

Hospital officials said Saturday that Nasheed is conscious and no longer needs breathing support. Two of his bodyguards and two apparent bystanders, including a British citizen, were also wounded in Thursday’s blast.

Prosecutor General Hussain Shameem told reporters that investigators still do not know which extremist group was behind the attack, which left Nasheed, 53, in critical condition in an intensive care unit after life-saving surgeries to his head, chest, abdomen and limbs. No group has claimed responsibility.

Nasheed, the current Parliament speaker, has been an outspoken critic of religious extremism in the predominantly Sunni Muslim nation, where preaching and practicing other faiths are banned by law. He has also been criticized by religious hard-liners for his closeness to the west and liberal policies.

Police announced Saturday that two men were arrested in connection with the attack, and released photos of two others seeking public assistance in identifying them.

Authorities say a homemade explosive device contained ball bearings was attached to a motorbike parked near Nasheed’s car. The device was detonated, possibly with the use of a remote control, as he was about to leave home for an event.

He was the first democratically elected president of the Indian Ocean archipelago, serving from 2008 to 2012, when he resigned amid protests. He was defeated in the following presidential election, and was ineligible for the 2018 election due to a prison sentence, but has remained an influential political figure.

Nasheed has championed global efforts to fight climate change, particularly warning that rising seas caused by global warming threaten the archipelago nation's low-lying islands.

The Maldives is known for its luxury resorts but has experienced occasional violent attacks. In 2007, a blast in a park in the capital wounded 12 foreign tourists, which was also blamed on religious extremists.

The Maldives has one of the highest per capita numbers of militants who fought in Syria and Iraq alongside the Islamic State group.

Authorities announced in January that eight people arrested in November were found to have been planning to attack a school and were in the process of building bombs in a boat at sea. Police said the suspects conducted military training on uninhabited islands and recruited children.