Hemant Soren, a former deputy chief minister and son of JMM chief Shibu Soren, said in New Delhi that the Congress had promised to prop up a JMM government.
He added that the JMM and the Congress would fight the 2014 Lok Sabha election together.
Hemant Soren has been in New Delhi for four days, engaged in negotiations with Congress leader B K Hariprasad, who is in charge of Jharkhand, and others.
According to a Congress source, the Congress will contest 10 of the 14 Lok Sabha seats in the state, leaving the JMM to field candidates in the remaining four seats.
The Rashtriya Janata Dal has also announced its support to a JMM government.
“We have extended our support to a JMM-led government in Jharkhand,” party leader Lalu Prasad said in Patna.
“Hemant Soren will lead the new government. The President’s Rule should end and a popular government should be formed.”
JMM leaders claim the support of 42 legislators in the 82-member state assembly.
The JMM, Congress and RJD have 18, 13 and five legislators respectively. JMM says it will also get the backing of seven legislators who are either independent or belong to smaller parties.
The six-month President’s Rule is set to end July 18.
If the JMM does form a government, it will be the ninth government in Jharkhand since it was carved out of Bihar in 2000.