Thailand blast
[Representational Image]Reuters

A bomb blast in a hospital in Thailand's capital Bangkok injured at least 24 people on Monday, police said.

The blast occurred at Phramongkutklao Hospital, which is popular with retired military officers. The explosion happened three years to the day since the military took power in a coup.

Investigators reportedly have found traces of batteries and wires at the scene of the incident. Reports state that the explosive had been hidden in a container near the hospital's pharmacy.

Most of the people who were wounded in the incident were hit by shards of glassed flying at the scene.

According to a government spokesperson three people have received serious shrapnel injuries to the face and neck. The rest of the victims, however, had minor wounds.

"It was a bomb. We found the pieces that were used to make the bomb. Right now, authorities are checking out closed circuit cameras," Commander Kamthorn Aucharoen said, according to Sky News reports.

Human Rights Watch described the attack as a "cruel and inhumane action which grossly violates human rights".

No terrorism outfit has claimed responsibility for the attack. The authorities however suspect the assailants to be political dissidents opposed to military rule or Muslim separatists based in the south of the predominately Buddhist nation.

The explosion comes two weeks after a double blast at a shopping centre in Pattani in southern Thailand. The multiple blasts earlier this month had injured at least 50 people. The authorities had blamed the attack on Muslim insurgents.

A suspected car bomb was detonated at the entrance to the Big-C shopping centre in downtown Pattani on May 9, a province that has suffered waves of secessionist violence since 2004.

The first bomb was reportedly detonated inside the building, followed by a second explosion outside the centre, which targeted shoppers running from the first blast.