BANGKOK (AP) — A grenade exploded near a Bangkok shopping mall early Friday, injuring one person and rattling the Thai capital less than a week after a similar blast left a bystander dead and several more hospitalized.

Authorities have declined to speculate if the explosions are linked to the country's ongoing political turbulence.

The latest grenade was hidden in a garbage bag and placed alongside other trash bags in front of a residential building opposite the King Power duty-free shopping center in the Din Daeng neighborhood of Bangkok, said police Capt. Nitti Niruttiwat. It exploded at 1:30 a.m. and seriously injured a bystander, he said.

"The bomb squad found the safety pin of a grenade amid the debris at the crime scene and the area was reeking with petrol," he told The Associated Press, adding that investigators had not yet determined how the blast was triggered.

On Sunday, a grenade exploded near a bus stop in another part of downtown Bangkok, killing one person and wounding 10.