Four people were killed and nearly 30 wounded when a bomb attached to a motorbike went off near a crowd of protesters in southern Nepal on Monday, April 30 police said, according to AFP.

The group of 150 demonstrators in the city of Janakpur, 20 kilometres (12 miles) from the Indian border, were staging a sit-in to demand a separate province for Maithili-speaking people when the bike exploded.

"One of the protesters died on the spot while three died on their way to hospital. We have referred around seven seriously injured victims for treatment to Kathmandu," local police chief Basanta Raj Gautam told AFP.

"Over 20 people who sustained minor injures from the blast are being treated at various hospitals in the district."

The protesters had been taking part in a strike in Janakpur to demand the new province in the southern Terai plains. The Maithili language is spoken in eastern India and southeast Nepal.

Nepal has been relatively peaceful since rebel Maoists waging a 10-year war against the government signed a peace accord in 2006.

The country's parliament is nearing a deadline to write a peacetime constitution which will divide the country into new federal states.