The move is unlikely to pose any threat to the government.
The BJP-led government in Manipur lost a minor ally on Friday over the ethnic violence raging in the northeastern state for over three months.
Kuki People's Alliance, which has two MLAs, announced their withdrawal of support in a letter e-mailed to Governor Anusuiya Uikey. The move is unlikely to pose any threat to Chief Minister Biren Singh's government.
"After careful consideration of the current conflagration, the continued support for the incumbent government of Manipur led by Chief Minister N Biren Singh is no longer fructuous. Accordingly, the support of the KPA to the Government of Manipur is hereby withdrawn and can be considered null and void," said the letter by KPA chief Tongmang Haokip.
KPA leaders had attended the July 18 meeting of National Democratic Alliance (NDA) partners in New Delhi.
Kimneo Haokip Hangshing from Saikul and Chinlunthang from Singhat are the two KPA MLAs in the 60-member assembly. The BJP, which has 32 MLAs, is backed by five legislators from Naga People's Front (NPF), seven from National People's Party (NPP), six from JDU, and two Independents.
Of them, 10 MLAs including seven from BJP have demanded separate administrations for the Kuki-dominated districts.
KPA's move comes a day after Manipur witnessed one of its deadliest days in a fortnight on Saturday. Six deaths and day-long mortar and grenade attacks marked Saturday along the Bishnupur-Churachandpur border.
Amid rising tensions, the Centre sent 900 more security personnel to Imphal last night to be deployed across the strife-torn state. The home ministry has earlier deployed over 40,000 personnel of the army and paramilitary forces in the state since the clashes began on May 3.
The violence broke out in Manipur between the Kuki tribe and the Meiteis over the Meiteis' demand for Scheduled Tribes (ST) status. At least 170 people have been killed and thousands internally displaced since then.