KATHMANDU (Reuters) - Four people were killed and seven others injured on Sunday in three separate explosions in the Nepali capital, Kathmandu, and police said they suspected a Maoist splinter group may have been responsible.

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“Three people were killed on the spot and the fourth one died while undergoing treatment at a hospital,” police official Shyam Lal Gyawali said, adding that the nature of the blasts was under investigation.

One person was killed in an explosion inside a house in the Ghattekulo residential area in the heart of the city.

“I heard a big noise and rushed to the spot to find the walls of a house had developed cracks due to the impact of the blast,” 17-year-old student Govinda Bhandari told Reuters at the site of the first blast.

The second blast took place near a hairdresser’s in the Sukedhara area on the outskirts of the city, where three people were killed.

The third blast, a crude device, went off near a brick kiln in the Thankot area of Kathmandu, injuring two people, police said.

All of the seven injured people were taken to hospital.

A Reuters photographer at the site of the second blast said it had shattered the door and window panes of the shop and the area had been sealed off by the army.

Gyawali, the police official, said they suspect the blasts may have been the work of a splinter group of former Maoist rebels who are opposed to the government for arresting its supporters.

“A pamphlet from the group has been found at the site of the first blast,” Gyawali said.

The house was used to make improvised or crude explosive devices by activists from the group, he said, adding that one of the injured people was a supporter.

Nepal emerged from a decade-long Maoist civil war in 2006 and the main group of the former rebels has joined the party that runs the government now.

The breakaway group of former rebels carried out a similar blast in Kathmandu in February, in which one person was killed and two others were injured.

No one has claimed responsibility for Sunday’s blasts.