A powerful bomb exploded near the Nepal telecom office in southern Nepal's Parsa district killing one person and injuring five others, police said.

The bomb planted by unidentified persons exploded near the gate of the company's regional office at Ghantaghar Chowk in Birgunj town on Thursday evening, the police said, adding a few suspects have been detained.

Security has been beefed up in the area. No one has so far claimed responsibility for the blast.

Meanwhile, the Kathmandu District Court on Thursday refused bail to four accused in the triple blast that rocked Kathmandu on September 2, killing three people.

They have been sent to jail for further investigation, officials said.

The court has also issued arrest warrants against five others who are absconding.