A blast went off just outside the home of Nepal's vice president in a Kathmandu suburb on Friday, injuring one person, police said.
Vice President Paramananda Jha, who was at home at the time, was unhurt, his family said.
"It was a big explosion outside the house but no one from the family is injured," said Jyoti Jha, an aide of the leader.
Police said it was not clear who planted the explosive.
Jha, a member of the minority ethnic Madheshi community dominating Nepal's southern plains, has been in the news since he took the oath of office last year in the Hindi language rather than Nepali, sparking angry protests.
A security guard was injured in a similar blast at his home last year.
Last week the Supreme Court ruled that the "legality of the vice-presidency will not be recognized" if Jha fails to retake the oath using the Nepali language in seven days.
Political parties based in the Himalayan nation's southern plains called the ruling "prejudiced" and say the vice president need not take the oath again.
The Madheshi parties prop up the ruling coalition. Hindi is not an official language but is widely spoken in the southern plains.
Prime Minister Madhav Kumar Nepal has urged Jha to take the oath in Nepali and respect the court order.
The row has become a headache for the government formed after Maoist former rebels quit amid a row over the firing of the country's army chief.
Jha was elected Nepal's first vice president last year after the Himalayan nation abolished the 239-year-old monarchy and became a republic.
(For the latest Reuters news on Nepal see: http://in.reuters.com, for blogs see http://blogs.reuters.com/in)
