Anti-arms activists have pledged to mount the biggest-ever demonstrations in an effort to disrupt Europe's biggest arms show, which opens in London today.
Scotland Yard said 61 people were arrested ahead of the Defence Systems & Equipment International (DSEi) event opening today at the ExCel Centre in east London's Royal Docks.
Police in London are today mounting a massive security operation around the event.
Military top brass and defence ministers from a number of countries including Algeria, Angola, Colombia, Pakistan and India are expected to attend the show, which lasts until Friday, to see exhibits from some 950 companies.
A spokesman for protest group the Campaign Against the Arms Trade (CAAT) said that between 30 and 40 people had attended the event billed as "a silent witness against the arms trade".
A spokesman said the group would attempt to disrupt the event in a number of ways, including holding a procession to the east London venue this morning.
Some individuals were expected to try to gain access to high-security event, the spokesman said, but added the CAAT action would be non-violent.
"This arms fair is a bringing together of companies and countries with terrible track records," he 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."
Reclaim the Streets is due to hold a street party in the Docklands area tomorrow - which has been designated a day of "wildcat" direct action by activists.
PA