NEW DELHI — An explosion in a crowded flower market in India’s capital Saturday killed a 13-year-old boy and injured 18 others, police and hospital officials said.

Seven of the wounded were in critical condition, said Sanjeev, a spokesman for the state-run All India Institute for Medical Sciences who uses only one name.

“The boy was brought dead to the hospital,” Mr. Sanjeev told reporters.

No one immediately claimed responsibility for the blast.

Police spokesman Rajan Bhagat said police were investigating the nature of the explosive and described it “as a low-intensity blast.”

Witnesses saw two young men on a motorbike drop a black package in the middle of the road in the Mehrauli area of southern New Delhi, deputy police commissioner H.G.S. Dhaliwal told reporters. The area has a mixed population of Hindus and Muslims.

The package exploded after it was picked up by the teenage boy, who shouted at the motorbike riders that they had dropped their package, Mr. Dhaliwal said.

TV images showed a small crater in the road. Many people, including wailing women, searched for their relatives.

People walked in bloodstained shirts as the explosion created chaos in the market filled with weekend shoppers.

The road was splattered with blood and broken glass was strewn in the area.

Police cordoned off the area as fire engines and ambulances rushed to the scene.

The blast occurred two weeks after a series of bomb explosions struck a park and crowded shopping areas in the capital, killing 21 people and wounding about 100 others.

A group calling itself the Indian Mujahideen claimed responsibility for that attack.

Police believe the group is a front for the Students’ Islamic Movement of India, which was banned in 2001.

The Indian Mujahideen also claimed responsibility for bombings in the western city of Jaipur in May that killed 61 people and in the western state of Gujarat in July that killed at least 45.

India has routinely blamed Pakistani or Bangladesh-based militant groups for dozens of attacks in the last three years. But evidence has increasingly pointed to the involvement of Indian Muslims, raising difficult questions for the government about growing anger among India’s large Muslim minority.

India’s Muslims, who account for about 14 percent of the population of about 1.1 billion, lag far behind the Hindu majority in almost every social indicator, from household income to literacy.