New Delhi  -  India's capital was under a virtual state of siege Thursday as Tibetans held widespread protests and made several attempts to breach security ahead of the Olympic torch run in New Delhi.

More than 50 Tibetans were detained across the city since early Thursday. Police arrested 30 protesters who tried to block traffic on the road as the Olympic flame was being taken under heavy security from the international airport to a hotel, police said.

Tibetan exiles wearing "Free Tibet" shirts and holding Tibetan flags also made two attempts to barge into the Le Meridien hotel where the torch was kept.

The NDTV network reported that 18 Tibetans were stopped before they could breach the security and whisked away to a local police station.

The report said another five protestors shouting anti-China slogans were detained by the police from near the relay route in India Gate.

Elsewhere, 45 Tibetans were held in the western city of Mumbai after they tried to hold a protest rally near the Chinese consulate, the PTI news agency reported.

In the eastern town of Siliguri, 30 Tibetans went on a hunger-strike in protest against China's crackdown on the Tibetan unrest.

The Olympic torch arrived in Delhi from Islamabad shortly after 1 am and was received by Indian Olympic Association president Suresh Kalmadi and Chinese envoy Zhang Yan amid heavy police presence.

Nervous authorities mounted unprecedented security arrangements anticipating that radical Tibetan activists could stage violent protests or try to immolate themselves.

In Delhi, nearly 15,000 police and paramilitary personnel as well as surveillance helicopters were guarding the 2.6-kilometre stretch between the presidential palace and India Gate, the venue of the torch relay to be held late Thursday afternoon.

Commandos from the elite National Security Guard will be on guard to prevent any attempt to disrupt the run in the area, which was sealed off to vehicular traffic.

Besides 70 torchbearers, including former Indian Olympic Games participants tennis player Leander Paes and athletes Anju Bobby George and PT Usha, only participating schoolchildren and special IOA invitees will be allowed at the venue.

All doors and windows of buildings facing the relay route will remain closed from 1 pm to 6 pm and office workers would not be allowed to enter or leave the area or to be on rooftops.

Tight security was also in place near the Chinese embassy and on routes near the international airport where protests were expected during the day.

Huge numbers of police were deployed near Rajghat, the memorial to Mahatma Gandhi, from where hundreds of Tibetans staged a parallel torch relay, calling it the "Torch for Tibet" and the "lamp of light and freedom".

"Olympics stand for peace and harmony. There's no harmony in China," said Tenzin Choeying, the head of the Students for Free Tibet, India chapter. "China does not deserve this torch."

Tibetan refugee groups in India have been holding protests leading up to the torch relay and the Beijing Olympics, saying they want to use the occasion to draw international attention to China's human rights violations in Tibet.

The India leg of the torch relay is considered one of the most sensitive, as the country is home to about 100,000 Tibetan refugees, estimated to the largest concentration of Tibetans outside Tibet.

Local media reported that India's ace shooter, Jaspal Rana, boxer Vijender Kumar and musician Ayaan Ali Khan had pulled out of the torch relay at the last minute. Kumar confirmed that he had withdrawn from the relay to show support for the Tibetan cause.

Four Indian personalities including Indian football captain Baichung Bhutia, cricketer Sachin Tendulkar, former police official Kiran Bedi and film star Soha Ali Khan have already withdrawn from the relay for different reasons. (dpa)