Defence ministers and senior army officers from countries including Algeria, Angola, Colombia, India and Pakistan were expected to attend the exhibition over four days to see military hardware showcased by some 950 companies.

More than 2,600 security personnel were deployed at the Defence Systems and Equipment International show, held at the Royal Docks in east London.

Six warships were docked alongside the exhibition centre, with a Eurofighter Typhoon jet fighter and a US Apache attack helicopter displayed in the main hall.

A small group of demonstrators shouted "Shame on you!" at delegates queuing to get in, but made no attempt to break through security cordons.

Nearby, protesters congregated holding banners, chanting peace slogans and listening to music.

London's Evening Standard newspaper put the figure at 1,500, but police said there were around 200 demonstrators.

Police said they had arrested 17 people Tuesday, mainly for obstructing the highway, as well as another 51 people in the week running up to the event.

About half the exhibitors at the show were British firms, with 20 percent from the United States and the remainder from other NATO countries.

Several companies were showing off systems that can be installed on civilian aircraft to ward off or confuse surface-to-air missiles.

The Times newspaper reported on Friday that British Airways had begun talks with Boeing, a leading US defense contractor, and European aircraft maker Airbus about installing anti-missile technology on its planes.

Opening the London exhibition, Defence Secretary Geoff Hoon underlined the importance of the defence industry in a world confronted with the threat of terrorism.

Hoon said: "We live in a fast-changing and uncertain world. The appalling terrorist attacks of 11th September 2001, and others since, have proved as much.

"We found that we must be prepared to intervene militarily or otherwise to confront the threat posed by international terrorism."

The officer in charge of policing the exhibition said last week that he was concerned that protests by anti-arms and anti-globalisation groups could turn into a riot.

Metropolitan Police deputy assistant commissioner Andy Trotter said: "Our concern would be if the demonstration turns into riots and we have got to be prepared to deal with that."

A spokesman for protest group the Campaign Against the Arms Trade said the organisation would attempt to disrupt the show.

"This arms fair is a bringing together of companies and countries with terrible track records," the spokesman said.

"First and foremost we hope we will get it cancelled, or create a public outcry big enough to make sure it doesn't happen again."

A spokesman for the Ministry of Defence's Export Services Organisation pointed out that Britain had "strict export licence criteria, and going to the exhibition in no way implies that you can buy the equipment."

The spokesman added: "Defence brings five billion pounds (eight billion dollars, seven billion euros) a year to the UK and benefits between 70,000 and 100,000 jobs."

WAR.WIRE