The United States, Russia and other nations will sign an agreement Thursday to coordinate Arctic search-and-rescue missions, and begin planning how to prevent a catastrophic oil spill as they rush to exploit some of the world's richest remaining fuel deposits.

Secretary of State Hillary Rodham Clinton said the meeting of the eight-nation Arctic Council will highlight the growing importance of the Earth's northerly frontier, where melting icecaps are opening new shipping routes, fishing grounds and oil and gas drilling.

Clinton and Interior Minister Ken Salazar were heading the large American delegation in Nuuk, Greenland's capital. Russia, Canada, Norway, Sweden, Finland, Denmark and Iceland are also represented at the gathering.