LONDON — A group of investors representing more than 5 trillion euros (about $5.53 trillion) in assets under management have called on oil and gas companies to observe an unlimited moratorium on activity in the Arctic high seas.

Led by French asset managers Mirova and Natixis Asset Management, the group of 19 investors said it was an "urgent call" to protect the hydrocarbon-rich region from future exploration and reflected national pledges on climate change.

"We would like to involve both companies and policymakers so as to take the Arctic issue to the next level and seek greater protection for the region," said Mirova Chief Executive Philippe Zaouati in a statement on Monday.

The group said countries should take into account national climate pledges before granting new licenses or extending existing ones. They should also apply stricter, common criteria to ongoing projects and restrict approval to those presenting minimal operational risks.

Oil and gas companies, meanwhile, should stop drilling in Arctic marine waters covered by ice "due to current technological uncertainty in terms of the effectiveness of oil recovery mechanisms" and avoid areas of ecological significance.

The group also called on oil firms to publicly disclose their licenses held in the region, whether they intend to use or extend them and how these plans fit with their broader climate change mitigation commitments.

Reporting by Simon Jessop.