Congress leader Rahul Gandhi and several other party MPs were detained by police at Vijay Chowk here on Tuesday after they staged a protest against Sonia Gandhi's questioning by the Enforcement Directorate.

The former Congress president and the MPs had gathered at the Vijay Chowk to march towards the Rashtrapati Bhavan to draw the President's attention to the alleged misuse of central agencies by the government, but were stopped by the police.

Gandhi was put in a police bus but officials did not disclose where he was being taken. Other Congress MPs were detained and taken away in separate police buses.

"India is a police state, Modi is a king," Rahul Gandhi alleged.

He said discussions were not being allowed in Parliament.

"I am not going anywhere. We wanted to go towards the President's house. But the police are not allowing us," Gandhi said.

"All Congress MPs stopped at Vijay Chowk and prevented from marching to Rashtrapati Bhavan. Forcibly arrested. Now we are in police buses being taken to a place only PM and HM know where," Congress Rajya Sabha MP Jairam Ramesh tweeted.

"The Delhi Police harassed us. They have taken almost all the 75 MPs under detention and are taking them to unknown places," said Manickam Tagore.

Ernakulam MP Hibi Eden said, "We were holding a peaceful protest to give a petition to the President of India, but were attacked by the police. All the MPs, including Rahul Gandhi, have been arrested and taken to police stations."

The Congress MPs met earlier in the Parliament complex to decide on a strategy as party chief Sonia Gandhi appeared before the ED for questioning in a money laundering case pertaining to the National Herald newspaper, for the second time.

They also staged a protest in front of Mahatma Gandhi's statue in the complex.

AICC general secretary Ajay Maken claimed they were denied permission to organise a satyagraha outside Rajghat, the memorial of Mahatma Gandhi.

Rahul Gandhi, along with other MPs of Congress, was detained by Delhi Police from Vijay Chowk. Twitter

Rahul Gandhi was also questioned by the ED in the same case last month in sessions that clocked more than 50 hours over five days.

In another part of the city, Rahul's mother and Congress president Sonia Gandhi was at the Enforcement Directorate for the second round of questioning in connection with the National Herald case, reports ndtv.com.

Sonia Gandhi was accompanied by her daughter Priyanka Gandhi Vadra to the probe agency's office. Rahul Gandhi also went there before joining the protest at Parliament.

The Congress MPs were protesting against the Opposition "being silenced" in Parliament a day after four party MPs were suspended for the entire monsoon session. The MPs, who planned to march towards the Rashtrapati Bhavan, were stopped at the Vijay Chowk crossing.

"We're protesting as per the instruction of the police. All of this is a conspiracy by PM Modi and Amit Shah to completely destroy the Opposition and muzzle our voices. We won't be scared, our fight will continue," said Congress leader Mallikarjun Kharge, the Leader of Opposition in Rajya Sabha.