Two small bomb explosions outside a major shopping mall in Thailand's capital were aimed at discrediting the military government, the junta leader said Monday.

The government has been under heavy pressure to lift martial law, which has been in place since a coup last May removed an elected government. Analysts say the junta is likely to use Sunday's blasts as a reason to prolong martial law.

Police said they expect to issue arrest warrants in a few days. One person was slightly injured in the explosions on a walkway between the upscale Siam Paragon mall and an elevated mass transit "Skytrain" station, which was undamaged but briefly shut as a precaution.

Junta leader and Prime Minister Prayuth Chan-ocha told reporters that security measures will be intensified as a result of the blasts.

Asked if the perpetrators chose the location to discredit the government, Prayuth replied, "Everybody knows that. Otherwise they would have exploded the bombs in the jungle. Why the hell are you asking this?"

An increased security presence was visible Monday at the Skytrain station. Officers went up and down escalators with pointing devices, examining the ground closely and conferring in small groups as commuters passed.

Police said the small homemade bombs were designed to sow panic, not kill.

"The explosions were caused by two pipe bombs, but the flash powder that was used had low pressure. You can see that the damage was not much," national police spokesman Lt. Gen. Prawut Thawornsiri said Monday.

"We have not ruled out the possibility that it was politically motivated but we are pursuing all kinds of motives," he said.

Police were looking for two males seen on surveillance video and will likely issue arrest warrants for them in a few days, police Col. Kamthorn Auicharoen said.

Political temperatures have risen somewhat as the ruling junta has tightened its clampdown on critics. The explosions came a little more than a week after the junta-appointed legislature formally impeached former Prime Minister Yingluck Shinawatra, the leader of the ousted government.

Ambika Ahuja, an analyst with the Eurasia Group consultancy, said junta leaders are likely to use the explosions "to strengthen their case to tighten security in the capital and keep martial law in place despite increased pressure from foreign governments, domestic business leaders, and tourism operators to revoke the security law."

Asked about opposition allegations that the government staged the attack to prolong martial law, army chief Gen. Udomdej Sitabutr told reporters, "They can say whatever, but state authorities would never do such thing. We are straightforward and don't need to fabricate things."

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Associated Press writer Ted Anthony contributed to this report.