Thai forensic experts carry evidence as they leaves from a site of bomb blast at the Phramongkutklao Hospital, in Bangkok, Thailand, May 22, 2017. REUTERS/Athit Perawongmetha

BANGKOK (Reuters) - Thai authorities have arrested a 62-year-old man in connection with a bomb attack at a military-owned hospital in Bangkok that wounded 24 people last month, the defense minister said on Thursday.

The May 22 attack at the Phramongkutklao Hospital, in central Bangkok, came on the third anniversary of the army’s seizure of power, and the army initially blamed the bombing on groups opposed to military rule.

Defense Minister Prawit Wongsuwan told reporters a male suspect was being interrogated over the attack, but gave no indication of any motive or affiliation.

There was no claim of responsibility for the blast at the hospital, which is popular with soldiers and their families and retired military officers.

The bombing followed a small blast that wounded two people on May 15 at the National Theater in the Thai capital, and the junta promised to increase security to reassure foreigners in one of the world’s most visited tourist destinations.

Thailand has been ruled by a junta since a coup in May 2014 and after the hospital attack, Prime Minister Prayuth Chan-ocha raised the possibility that violence could lead to a further delay to elections now scheduled for next year.

Bombings are frequent in the country’s far south, home to a long-running Muslim separatist insurgency, but attacks by the rebels have largely been confined to their southern heartland.

Deputy national police chief Srivara Ransibrahmanakul told reporters the investigation of the Bangkok hospital bombing had made satisfactory progress, but he did not confirm the arrest.