WASHINGTON, June 8 (Reuters) - Britain and the United States backed a new "Atlantic Declaration" on Thursday for greater cooperation on pressing economic challenges in areas like clean energy, critical minerals and artificial intelligence.

The joint declaration described the partnership as the "first of its kind" in covering the broad spectrum of the two countries' economic, technological, commercial and trade relations.

Under the plan, Britain and the United States will strengthen their supply chains, develop technologies of the future and invest in one another's industries, British Prime Minister Rishi Sunak's office said.

Sunak and U.S. President Joe Biden also agreed to launch a new civil nuclear partnership as part of their clean energy cooperation, which will include setting up new infrastructure over the long term and cutting reliance on Russian fuel.

The two countries also agreed to work together on ensuring the safe development of AU technology, starting with Britain hosting a global summit later this year.

The United States was looking to Britain to help lead a common approach on AI safety and regulation, Biden said at a joint news conference with Sunak in Washington.

The two nations will also begin negotiations on a critical minerals agreement, which would allow some UK firms to access tax credits available under the U.S. Inflation Reduction Act.

The minerals, such as lithium, nickel, cobalt, graphite and manganese, are critical for batteries for electric cars, smartphones and solar panels.

Britain and the United States will also co-operate on telecoms technology including 5G and 6G and quantum technologies, the Atlantic Declaration said.

The declaration also included a commitment in principle to a UK-U.S. "data bridge" which would make it easier for British businesses to transfer data freely to U.S. organisations without red tape.