Police in the Maldives announced on Sunday that they had apprehended a person suspected of being the main suspect in an explosion that seriously injured the country's former president and was blamed on Muslim extremists.

Three of the four suspects in Thursday's blast targeting former President Mohamed Nasheed, who is recovering in a hospital after several surgeries, are now in police custody.

Police did not provide any information about the new suspect or his past, but they did confirm in a text message that they assume he is the person whose photos were released Saturday as authorities sought public help in identifying him. The last suspect is also on the loose.

Officials blamed the attack on Islamic extremists.

Prosecutor General Hussain Shameem told reporters on Saturday that investigators are still trying to figure out who was behind the attack. Two of Nasheed's bodyguards were also injured, as were two bystanders, one of whom was a British resident.

Nasheed had long talks with some family members, according to a relative who tweeted early Sunday.

Nasheed, 53, is still in intensive care after undergoing life-saving surgery on his head, face, abdomen, and limbs, according to hospital officials.

They told reporters that shrapnel from the explosion had injured his intestines and liver and that a piece of shrapnel had broken his rib and was less than a centimeter (0.4 inches) from his core.

Nasheed is the current Speaker of Parliament and has been a vocal opponent of religious extremism in the predominantly Sunni Muslim nation, where preaching and practicing other faiths is illegal. Religious fundamentalists have chastised him for his links to the West and liberal policies.

Following a letter from the Maldives, officers from the Australian Federal Police were helping with the inquiry. On Sunday, a British investigator was scheduled to arrive in the Indian Ocean archipelago.

Nasheed served as the Maldives' first democratically elected president from 2008 to 2012, when he resigned amid protests. He was defeated in the ensuing presidential election, and due to a prison term, he was unable to run in the 2018 election, but he has remained a powerful political figure.

He has advocated for global efforts to combat climate change, warning that rising seas due to global warming pose a danger to the archipelago nation's low-lying islands.

The Maldives is renowned for its luxurious resorts, but it has also been the site of violent attacks on occasion. Twelve international visitors were injured in a blast in a park in the capital in 2007, which was also blamed on religious extremists.

The Maldives has one of the largest per capita numbers of militants fighting against the Islamic State group in Syria and Iraq.

Authorities reported in January that eight people arrested in November were found to be plotting a school attack and were constructing explosives in a boat at sea. The suspects allegedly conducted military training on uninhabited islands and recruited children, according to police.