Uttar Pradesh Minister Anand Sen Yadav on Tuesday resigned following allegations of being involved in the kidnapping of a Dalit girl and the state government ordered a Central Bureau of Investigation probe into the whole matter.

Chief Minister Mayawati asked Anand Sen, minister of state with independent charge who has several criminal cases against him, to put in his papers in the wake of the allegations levelled against him by family members of the girl who went missing from Faizabad on October 22.

The government also ordered a CBI inquiry into the matter, official sources said.

The issue rocked the state assembly where leader of the opposition and former chief minister Mulayam Singh Yadav alleged the girl was pregnant and demanded a high-level inquiry.

Talking to mediapersons, the girl's father Yogendra Prasad alleged she had been kidnapped and he suspected the involvement of the minister who was close to the family.

"I suspect the involvement of the minister, his driver and a woman in this. I have filed a complaint but no one is taking action. I am afraid she might have been killed by now," he said.

He also claimed that despite an FIR lodged, police did not take any action against the suspects.

The minister's driver Vijay Sen, who was arrested earlier, was released under pressure from the minister, he alleged.

Meanwhile, the minister, who has a number of criminal cases pending against him, termed the allegations as baseless and said it was a part of a conspiracy by Samajwadi Party to defame him and the Bahujan Samaj Party government.

"I have already apprised my party of a conspiracy to target me," the minister said.

According a report from Faizabad, the driver of the minister told the police that the girl had committed suicide by jumping into Gomti river in Sultanpur.

Police sources said Vijay, who was produced before a court, was remanded to police custody for two days.

Cabinet Secretary Shashank Shekhar Singh told reporters that Anand Sen, who was in charge of food processing ministry, resigned on moral grounds so that an impartial probe could be conducted into the matter which has been referred to CBI.

Though no fact has come to the fore against the minister pointing the needle of suspision towards him, he has put in his papers to ensure an impartial probe, Singh said.

Singh also released to the press a letter written by the girl's father to divisional commissioner, Faizabad, on October 31 seeking an inquiry into the matter while praising the minister for extending all cooperation to the family.

Vijay, who was quizzed by the police in the matter, forfeited his bail in an old case and went to jail, apprehending arrest in this connection, the girl's father alleged.

Police sources claimed Vijay confessed to having kidnapped the girl.

Anand Sen could not be sworn in along with other ministers when the Mayawati government took oath of office in May 2007 as he was in jail.

Anand Sen's father and Bahujan Samaj Party Member of Parliament from Faizabad Mitra Sen Yadav's name had also figured in human trafficking case earlier.

Another UP minister Raghunath Prasad Shankhwar had earlier resigned after his name cropped up in a drug purchase scam.