The three blasts - one in the centre and two on the outskirts - took place last afternoon.
Improvised or crude explosive devices are believed to have been used to set off the blasts, and a Maoist splinter group was under suspicion after pamphlets were found nearby.
The same group is alleged to have carried out an explosion in February which killed one person in Kathmandu.
However, no one has claimed responsibilities for the attacks.