KATHMANDU, April 9 (Xinhua) -- At least 17 people were injured when members of a communist party faction and cadres of the ruling party, the Unified Communist Party of Nepal (Maoist) (UCPN-M) exchanged fire in eastern Nepal early Thursday, Nepali radio station, Nepal FM reported.

    Amid the clash in Biratnagar, some 240 km east of Nepali capital Kathmandu, 11 from UCPN-M and six from the Communist Party of Nepal(Maoist) (CPN-M) led by Matrika Yadav exchanged fire.

    The UCPN-M led by its chairman, Prime Minister Prachanda, changed the party name from the CPN-M after merging with another party named "the Communist Party of Nepal (Unity Center-Masal)" on Jan. 12, 2009.

    Matrika Yadav once was a senior leader of the former CPN-M. In September, 2008, he quitted the ministerial berth of Land Reforms following a controversial land capture row in the south of the country. Matrika Yadav later gave up his former CPN-M membership and formed a new " CPN-M" party in February, 2009.

    The two sides opened fire on each other early on Thursday morning following their disputes Wednesday over the issue of election rules, said Nepal FM.

    ABC Television, a local TV channel, said three of the injured have bullet wounds and the injured are receiving treatment at local hospital.

    The UCPN-M said three of its workers have gone missing after the clash. The clash had started after Matrika Yadav's men torched a vehicle used by ruling UCPN-M workers on Wednesday evening and allegedly abducted a UCPN-M worker.

    Meanwhile, Bijaya Kamat, the election candidate from Matrika Yadav's CPN-M from Morang Constituency-7 said his group attacked the vehicle as the ruling UCPN-M continued electioneering in violation of the election code of conduct, loal news website Myrepublica reported.

    Chief District Officer of Morang, Shashi Shekhar Shrestha, told Myrepublica reporter over phone that no one has been arrested so far.

    By-elections are scheduled for the coming Friday in six constituencies in five districts. Election code of conduct bars parties from campaigning from 72 hours before the elections.

    The by-elections will be held in six constituencies, including five becoming vacant after five Constituent Assembly members who won from two constituencies in the first-past-the-post CA elections held on April 10, 2008 gave up their positions.

    The winners of two constituencies included Prime Minister Prachanda who has vacated Rolpa-2 constituency and Law Minister Dev Gurung vacating Kaski-1 from the UCPN-M, Foreign Minister Upendra Yadav vacating Morang-5 and Works and Physical Planning Minister Bijaya Kumar Gachhadar vacating Morang-7 from the Madhesi People's Rights Forum, and Nepali Congress leader Sher Bahadur Deuba vacating Kanchanpur-4.

    President Ram Baran Yadav vacated his constituency of Dhanusa-5after being elected the president.

    Prachanda's party emerged from the CA elections as the single largest party in the house and led the formation of the republic government in August, 2008.