WASHINGTON (Reuters) - The United States and the Philippines announced a deal on Friday allowing for a rotating U.S. military presence at five Philippine bases under a security agreement inked amid rising tensions with China in the South China Sea.

A joint statement after an annual U.S.-Philippines Strategic Dialogue listed the sites as Antonio Bautista Air Base, close to the contested Spratly Islands in the South China Sea, Basa Air Base north of Manila, Fort Magsaysay in Palayan, Lumbia Air Base in Mindanao and Mactan-Benito Ebuen Air Base in Cebu.

U.S. Deputy Assistant Secretary of Defense Amy Searight said the deal was reached under a 2014 Enhanced Defense Cooperation Agreement (EDCA) that grants Washington increased military presence in its former colony through rotation of ships and aircraft for humanitarian and maritime security operations.

Searight told the meeting Manila was a “critical U.S. ally” and ties had never been stronger. She said U.S. Defense Secretary Ash Carter would visit the Philippines in April to discuss implementation of the agreement.

U.S. Ambassador to the Philippines Philip Goldberg told reporters movements of supplies and personnel to the base locations would take place “very soon.”

He described the agreement, valid for an initial 10 years, as “a pretty big deal,” that would allow for a greater U.S. presence as part of the U.S. rebalance to Asia and enhance the alliance with the Philippines.

However, he stressed that it did not allow for permanent U.S. bases that existed for 94 years until 1991, when the Philippine Senate voted to evict them.

“This isn’t a return to that era. These are different reasons and for 21st century issues, including maritime security,” he said, adding that all U.S. deployments would require Philippine approval.

The United States is keen to boost the military capabilities of East Asian countries and its own regional presence in the face of China’s assertive pursuit of territorial claims in the South China Sea, one of the world’s busiest trade routes.

U.S. Assistant Secretary of State Daniel Russel said Friday’s agreement came at an important time ahead of a ruling in a case the Philippines has brought against China over its South China Sea claims in the International Court of Arbitration in the Hague.

On Thursday, the U.S. Navy said it had seen activity around a reef China seized from the Philippines nearly four years ago that could be a precursor to more Chinese land reclamation in the South China Sea.

In an interview with Reuters, Navy chief Admiral John Richardson also expressed concern that the Hague ruling, which is expected in late May, could prompt Beijing to declare a South China Sea exclusion zone.

Searight said the Pentagon had told the U.S. Congress of its intention to provide $50 million to help build regional maritime security. She said the Philippines would get “the lion’s share” of the funds, which are expected to go toward improving radar and other South China Sea monitoring capabilities.