The Thailand government on Monday tightened its security in the country in response to two pipe bomb attacks on a Bangkok luxury mall one day earlier. The blasts only frayed the country’s nerves further, as investigations revealed the explosives to be homemade and not designed to kill. Thailand has been on tenterhooks ever since the junta government imposed martial law. The two attacks rocked the country’s relative calm for the first time since the military coup last May.

"I have ordered security to be tightened because this case involves the well-being of the people," Thai Prime Minister Prayuth Chan-ocha told reporters, according to Reuters. "This case shows that we still need martial law ... there are still bad people disrupting the peace. We must find ways to severely punish them."

No person or party has come forth to claim responsibility for the two attacks that happened near the Paragon luxury shopping center around 8 p.m., local time, in one of the city’s busiest shopping districts. Closed circuit television footage showed two possible suspects near the area of crime, but the image was unclear, the police told Reuters. Two people were injured in the incident.

The bombs were hidden behind electric controls, said Thai Royal Police spokesman Prawut Thawonsiri, according to the Bangkok Post, and only caused minimal damage. Authorities originally reported that the blasts were caused by a power transformer failure of a billboard, but admitted after several hours of investigations that bombs were responsible for the explosions.

The attack was most likely intended to cause panic rather than take lives, Prawut told the Bangkok Post. Defense Minister Prawit Wongsuwan said such violence rocks investors’ confidence in the country, according to Reuters. Thai social media speculated on Monday that junta supporters could have masterminded the attacks in order to justify the continuation of Prime Minister Prayuth’s martial law, according to Voice of America. The country has been officially under martial law since the junta’s military coup last May, and the government has asked for it to remain indefinitely for now, reported Reuters last November.

Prior to the attack, the ruling National Council for Peace and Order Party denied reports that the military regime was considering ending martial law, after it was criticized last week by the highest-ranking American diplomat to visit Thailand since the takeover. U.S. Assistant Secretary of State Daniel Russel said in a speech at a Bangkok university that the junta’s “political process doesn’t seem to represent all elements of Thai society,” according to VOA.

The country has been in political turmoil since the coup, as the civilian Yingluck Shinawatra government was deposed in a coup over a rice subsidy program last May, which eventually saw former Prime Minister Yingluck impeached and barred from politics for five years. Supporters of Yingluck and her brother Thaksin, himself also a former Prime Minister and now in exile, pitted themselves against the royalist junta that the country’s elite class favors.