[LONDON] Theresa May will use the Group of 20 summit in Hamburg to call for international coordination to track even small sums of money being transferred between terrorist groups.

The British prime minister will argue that new technology is needed to monitor such transactions, as they can provide clues to coming attacks.

She'll say that parts of the international finance system act as "safe spaces" for Islamic State and related groups, and suggest partnerships between police and banks to spot suspicious activity.

"We know that the terrorist threat is evolving," Mrs May said in a statement issued by her office.

"We must outpace the terrorist methodology as it develops to attack other vulnerable targets and increases inspired attacks. This includes taking measures against permissive environments for terrorist financing, and monitoring the dispersal of foreign fighters from battle."

Mrs May's focus on terrorism partly reflects Britain's vulnerability. The country has seen three Islamist-inspired attacks this year - on Parliament, on a Manchester pop concert and on Saturday-night drinkers at London Bridge. But it also reflects her own weakness, having lost her parliamentary majority at last month's snap general election.

Unlike Brexit, where her ministers are openly arguing about policy, counter-terrorism is an area where Mrs May, who was home secretary for six years before she became premier, is confident.

It was the subject about which she chose to speak at the United Nations last year and at this year's Group of Seven summit.

The G-20 gathering, being hosted by German Chancellor Angela Merkel, begins Friday amid high security as Germany's second-largest city prepares for escalating protests with the arrival of world leaders including US President Donald Trump and Russian President Vladimir Putin.

BLOOMBERG