BANGKOK — A bomb exploded at a popular shrine near a key political protest site in central Bangkok on Monday evening, the government said, reportedly killing more than a dozen people and injuring many others.

The bomb exploded inside the Erawan Shrine, and another undetonated bomb was found near the complex, said Maj. Gen. Weerachon Sukhondhapatipak, a spokesman for Thailand’s ruling junta. The shrine is a tourist landmark also popular with Thais.

Thai PBS television said at least 15 people were killed. Weerachon said dozens were injured, and that some foreigners were among the hurt.

The shrine is located at Rajprasong intersection, the center of many contentious political demonstrations in recent years.

Security video showed a powerful flash as the bomb exploded.

“We still don’t know for sure who did this and why,” Deputy Prime Minister Prawit Wongsuwon told reporters. “We are not sure if it is politically motivated, but they aim to harm our economy and we will hunt them down.”

Anusit Kunakorn, secretary of the National Security Council, said Prime Minister Prayuth Chan-ocha, the former army chief, was closely monitoring the situation.

Thailand’s capital has been relatively peaceful since a military coup ousted a civilian government in May last year after several months of sometimes violent political protests against the previous government. However, there has been some tension in recent months as the junta has made clear it may not hold elections until 2017 and wants a constitution that will allow some type of emergency rule to take the place of an elected government.