New Delhi/Mumbai/Guwahati, July 21 (IANS) Troubles mounted for Congress Monday as two senior ministers - Narayan Rane in poll-bound Maharashtra and Himanta Biswa Sarma in Assam - resigned from their posts signalling their desire to replace the incumbent chief ministers.

The resignations came even as the party is battling problems in poll-bound states of Haryana and Jammu and Kashmir and also in West Bengal where three of its legislators joined the ruling Trinamool Congress.

The Congress linked resignations of the two to their "personal ambitions" and denied it would affect the party.

The party had seen its worst performance in the Lok Sabha elections earlier this year and faces a tough challenge in the assembly elections expected to be held later this year in Haryana, Maharashtra and Jammu and Kashmir where it is in power.

The Congress had performed poorly in the three states in the Lok Sabha polls and has faced demands for change in leadership in Haryana and Maharashtra. In Jammu and Kashmir, it has decided to contest elections on its own by snapping ties with the National Conference.

Rane Monday resigned as Maharashtra's industry minister, the second time he resigned in the past two months.

He had announced his desire to step down last week and submitted his resignation to Chief Minister Prithviraj Chavan.

"I have resigned as minister but I shall continue to remain in the Congress," Rane said, scotching speculation that he might join some other party or float his own outfit.

The state Congress received another shock Saturday when seven of its Thane municipal corporators -- all staunch Rane supporters -- joined the Shiv Sena.

Rane had earlier quit as minister in May after his son and outgoing MP from Ratnagiri-Sindhudurg Nitesh Rane lost to the Shiv Sena in the Lok Sabha polls after a revolt by a section of the Nationalist Congress Party there. At that time, his resignation was rejected.

Rane, who was chief minister for nearly a year at the fag end of the Shiv Sena-BJP regime of 1995-99, quit the Shiv Sena to join the Congress in 2005, but never hid his ambition to become chief minister again and made several attempts to bag the post.

In Assam, Sarma resigned as minister, saying it was not possible "mentally, physically and politically" to work under Chief Minister Tarun Gogoi.

Sarma, who was holding health and education portfolios, submitted his resignation to Governor Janaki Ballabh Patnaik and declared he would continue to oppose the Gogoi government's anti-people policies within and outside the legislature.

"We are going to play the role of a constructive opposition in the assembly," said Sarma, who is believed to be leading a group of dissident Congress legislators.

He, however, added that he would obey the party whip.

Congress spokesperson Abhishek Manu Singhvi said that the two leaders had resigned due to their personal ambitions, saying Rane has been exhibiting this tendency and similar statements had come from Sarma.

"If it (the resignation) is on the basis of personal ambition, there is no alternative. Congress cannot say much," he said, noting the issue could not have been accommodated by the party leadership in the way the two leaders desired.

Singhvi denied that the Congress had suffered "a jolt" because of the resignations of the two ministers and emphasized that they continued to be in the party.

Congress leader Kamal Nath told reporters that Sarma's resignation was not a rebellion against party vice president Rahul Gandhi.

Adding to the travails, West Bengal legislators - Asit Kumar Mal (representing Hasan in Birbhum district), Mohammad Ghulam Rabbani (Goalpokhor in North Dinajpur district) and Umapada Bauri (Para in Purulia district) - joined the Trinamool in presence of Chief Minister Mamata Banerjee.

Meanwhile, it had also witnessed resignation of former Udhampur MP Chowdhary Lal Singh in Jammu and Kashmir Sunday.

In Haryana, senior leader Birender Singh has been pressing for resignation of Chief Minister Bhupinder Singh Hooda.