At least two bombs exploded Monday outside a venue in Nepal's capital where politicians are set to meet later this week to abolish the country's monarchy, police said.
Nobody was hurt in the attack, police said, adding that a previously unknown Hindu nationalist and possibly pro-royal group had left a leaflet at the scene claiming responsibility.
"Two explosions have occurred in front of the complex but there were no injuries," a police official, Durga Kumar, told AFP at the scene of the blasts.
"There would have been injuries but they threw the bombs where there were no people," the police officer said of the two attackers, who eyewitnesses said sped by on a motorcycle. "The people who did this are trying to create panic."
Nepal's Hindu monarch, King Gyanendra, is set to be ousted on Wednesday along with his 240-year-old Shah dynasty during the first meeting of a 601-member body elected last month to rewrite the country's constitution.
The April elections saw the country's Maoists win the largest bloc of seats in the assembly. The Maoists fought for a decade to overthrow the king, before signing a peace deal in 2006.
The king, however, is seen as still enjoying support from Hindu hardliners and powerful elements in the country's armed forces and ruling elite.
Tensions have mounted in Kathmandu ahead of the meeting, with the Maoists pouring tens of thousands of members of their feared youth wing into Kathmandu and authorities banning demonstrations.
"We are going to bring in 50,000 Young Communist League members to celebrate the declaration of a republic on Wednesday," said Sagar, head of the Maoists' youth wing, who goes by one name.
City authorities said they have banned demonstrations and mass meetings in four places around Kathmandu and are planning to deploy an extra 5,000 security personnel.
"The government has announced special prohibitory orders from today that forbid rallies or protests in certain sensitive areas including the royal palace and the constituent assembly venue," said Kathmandu police chief Sarbendra Khanal.
Royalists have warned that getting rid of the king, seen by devout supporters as the living incarnation of a Hindu god, could plunge the impoverished Himalayan country back into conflict.
Supporters of the monarchy also argue the institution is essential for maintaining the neutrality of a country wedged between Asian giants India and China.
"The constituent assembly does not have the mandate to decide the king's fate," argued Padam Sundar Lawoti, vice-chairman of the Rastriya Prajantantra Party-Nepal, a royalist party with four members in the new assembly.
"What they are doing is premature and illegal," he said.
Government officials, however, said that preparations for the historic meeting Wednesday that will end the world's last Hindu monarchy were complete.
"We have refurbished the hall of the Birendra International Convention Centre for the meeting, security arrangements have been made. We are all set," said Manohar Prasad Bhattarai, the acting secretary general of the Constituent Assembly.