President General Pervez Musharraf arrived in the port city of Karachi yesterday to inaugurate an exhibition of weapons and ammunition under an unprecedented security cover in the wake of the capture of key Al Qaida suspect Ramzi bin Al Shaibah in the port city last week.

Hundreds of army commandos, paramilitary Rangers and policemen threw a security net on the entire route from where Musharraf's motorcade had to pass and at the Expo Centre where the four-day defence exhibition - IDEAS 2002 - is being held.

"We don't know how many foreign and Pakistani extremists are still at large," said a senior police official, who asked not to be named.

Analysts said the the humid, lawless metropolis of more than 14 million people had many advantages for Taliban and Al Qaida militants who fled Afghanistan after the United States attacked the country last year.

Parking was banned since morning on all the possible routes of Musharraf's motorcade. Security officials were seen stopping vehicles and motorcyclists for snap checks, resulting in massive traffic jams and long queues of vehicles.

Authorities kept the time of Musharraf's arrival a tightly kept secret. "It took me more than one hour and a half to reach my office - double the time than my usual days," Iftikhar Ali, an employee at a private firm.

Rangers in combat gear stood alert at the rooftops near the Expo Centre, while the residents of the locality were not to stand in their balconies. Authorities also installed dozens of video cameras on the entire route on which Musharraf will travel.

Security has also been beefed up at the hotels where foreign delegates attending the exhibition are staying. Special arrangements have been made to ensure a foolproof security for foreign guests during their travel to exhibition and back to their hotels, police officials said.

Farooq Sattar, a former mayor of sprawling city, said Karachi was home to a number of underworld groups strong enough to provide protection to such militants for personal gain and coordination between law enforcement agencies was often poor.

"There is no central command in the city and it is very easy...(for militants) to hide and get protection from groups like drug and land mafias," he told Reuters.

There have already been at least two known assassination bids on Musharraf in Karachi in recent months.

On April 26, militants belonging to a little known Pakistani organisation, called Harakatul Mujahideen Al Alami, tried to blow up Musharraf's cavalcade by parking a vehicle packed with explosives on his route. But luckily the explosives failed to detonate.

Members belonging to the same group planned another attack a day after. But it too failed to materialise because Musahrraf delayed his arrival by at least three hours at site, where he had to inaugurate an expressway.

Both the cells of the militants have been arrested.

There is a lot of anger and bitterness among hardliners since Islamabad abandoned its longtime ally - the Afghan Taliban - and joined hands with the United States in destroying the network of militancy, they said.

A senior police official, who asked not to be identified, said that despite the recent arrests, Al Qaida elements might try to continue their struggle from hideouts in the city. "They have their sympathisers in the militant groups and religious schools, which are providing them safe havens," he said.

Jameel Yousuf, chief of the Citizen Police Liaison Committee, said that compared to other parts of Pakistan, Karachi is the best hiding place for militants on the run.