Bangalore/New Delhi, Jan 30 (IANS): Congress president Sonia Gandhi and vice president Rahul Gandhi did not interfere with the working of ministers, Congress leaders said Friday after former minister Jayanthi Natarajan quit the party.

Natarajan said there was interference in her work when she was the environment minister, followed by a campaign of vilification against her.

Congress leader and former union minister Veerappa Moily said Sonia Gandhi and Rahul Gandhi never interfered.

"I have handled several ministries. I have not come across any instance where the Congress president or vice-president interfered with administration. I don't know what made her to make that statement against discipline of the party," Moily told reporters in Bangalore.

"If a (former) minister says I did something because of interference, she is unfit of being a minister. I was also the chairman of media committee of Congress, even then there was no interference," he said.

He said the move may be motivated.

"Why did she send a letter and make it public? That means she is motivated," he said.

Party leader Digvijaya Singh said in Delhi: "I really don't know what was the issue. First of all it is totally wrong that either Sonia Gandhi or Rahul Gandhi ever interfered in the functioning of UPA government. Ministers were free to take decisions."

Natarajan quit the Congress after writing a letter to Sonia Gandhi, saying that as the union environment minister she followed the party line with regard to protection of environment and also to "requests" from Rahul Gandhi's office.