Thackeray welcomed her at a hurriedly convened media conference and said he was "happy that she had decided to join the Shiv Sena".

His son Aditya Thackeray presented her a bouquet and tied her a thread symbolizing 'Shiv Bandhan' with several senior party leaders in attendance.

Soon afterwards, Chaturvedi, 39, launched a scathing attack on the Congress, accusing it of not supporting her in the episode of unruly behaviour by some Congress activists.

"I have served the party (Congress) for 10 years in a selfless manner without asking for anything in return. But the party chose to ignore my complaints though the matter was taken up at the topmost level," Chaturvedi said, addressing the media in Hindi.

Chaturvedi said she had expressed her "pain" to the Congress leadership about the reinstatement of colleagues who misbehaved with her.

Though Chaturvedi admitted she was a bit disappointed at being overlooked for the Mathura Lok Sabha seat candidature, she insisted that the primary reason for quitting the Congress was the inaction against some activists who had misbehaved with her in the past.

Among her immediate priorities, she listed championing the cause of empowering women in politics and other fields besides helping "strengthen and build up Shiv Sena at the national level".

Mumbai-born and educated Chaturvedi described the city as "my 'janmabhoomi' and 'karmabhoomi', and the 53-year-old Shiv Sena as the 'roar' of Mumbai, Maharashtra and rest of the country".

On his part, Thackeray said the party would soon identify her responsibilities in Shiv Sena keeping in view her background and experiences and inform the media.

The announcement came within hours of her quitting the Congress in the midst of the Lok Sabha elections. Chaturvedi has been a prominent face of the Congress, articulating its viewpoint at press conferences and as a TV panelist.

In her letter to Congress President Rahul Gandhi on Thursday which became public on Friday, Chaturvedi said that in the last few weeks certain things had convinced her that her services were not valued in the party any more.

She said it saddened her that despite the safety, dignity and empowerment of women being promoted by the Congress, "the same is not reflected in the action of some of the members of the party".

"A serious incident and misbehaviour against me by certain party members while I was on official duty for the party has been ignored under the guise of all hands needed for elections. This indignity to me has been the final factor to convince me to move on and focus on other things outside INC," she wrote.

On Wednesday, Chaturvedi hit out at the Congress for reinstating members who had been suspended recently for misbehaving with her at a press conference in Mathura, saying "those who threatened her within the party got away with not even a rap".