New Delhi - Authorities have thrown a security blanket never seen for any head of state, with anti-Bush protestors pledging to take to the streets in thousands against the US President during his visit in New Delhi on March 1-3.

In an unprecedented act, Delhi Police have asked motorists to avoid several arterial roads in the heart of the city on Thursday when George W Bush will have a packed day in the Capital.

These include Connaught Place, Barakhamba Road, Kasturba Gandhi Marg, Janpath, Parliament Street, Jawaharlal Nehru Marg, Asaf Ali Road and Kamla Market.

A part of Ring Road that touches the Rajghat, Mahatma Gandhi's memorial, will also be out of bounds for traffic on Thursday.

Even bus routes in many of these areas have been curtailed.

Also on Thursday 50,000 to 100,000 people are expected to march from the Ramlila ground to Parliament Street, armed with posters, banners and Bush caricatures.

"We are protesting against everything Bush stands for," said Rajan, one of the organisers of Thursday's rally that will draw more than 100 small and big groups ranging from mainstream political parties to fringe outfits.

The office of Sahmat, a Left-leaning cultural body, is overflowing with a variety of anti-Bush stickers and posters and even T-shirts that mock at the US President, who is visiting India for the first time.

After initial hesitation, the police have finally relented and allowed the demonstrators to go up to Parliament Street, normally the venue of protests but a spot the authorities earlier did not want the anti-Bush rally to reach.

Delhi Police have told people working in thousands of offices located in and around downtown Connaught Place to positively make it to their work places by 9.30 am on Thursday, after which many roads will be sealed off for hours.

Even students appearing for their Class 10 and school-leaving examinations Thursday have been told to reach their respective centres in these areas by 8.30 am, almost two hours before the exams start.

"We appeal to the parents to make sure that their children reach the centres in north and central Delhi early. These areas would be under strict security as Bush goes from his hotel to Mahatma Gandhi's memorial," said Qamar Ahmad, joint commissioner of police (traffic).

"We know it will cause problems to students but arrangements have to be done for VIP movement," Ahmad said

Around the time Bush holds talks with Prime Minister Manmohan Singh at the stately Hyderabad House, thousands will gather at the Ramlila ground not very far away to kickstart a protest rally that is expected to take three hours to reach Parliament Street, less than a kilometre from Parliament House.

Both colourful and black-and-white posters denouncing Bush have sprouted on walls in many places.

Leaders of the Communist Party of India-Marxist (CPI-M), which supports the government but is opposed to Bush's visit, have assured the government that the protest would be peaceful.

The police, however, are taking no chances.

The mainstream political parties are not their worry but fringe groups are, outfits that might want to make an anti-Bush point violently. Among those ranged against the Bush visit is the Communist Party of India-Maoist, which believes in violence as a creed.

The US has brought in a mind-boggling array of security gear, including three helicopters, anti-aircraft guns, radio jammers and armoured limousines for the security of Bush. The airspace over Delhi will be sealed when Bush arrives and departs.

Tens of thousands of police and paramilitary personnel will be on duty during Bush's stay.

Even those not joining the New Delhi protests have expressed their anger against Bush.

"I am of course angry with Bush," said Syed Ahmed Bukhari, the Shahi Imam of Jama Masjid, India's largest mosque dating back to the 17th century. "But more than Bush I am angry at those who have invited him. This government calls itself secular and invites someone who is responsible for the death of Muslims in so many places including Iraq. What a shame!"