At a summit on Monday, U.S. President Joe Biden and his Philippine counterpart, Ferdinand Marcos Jr., are expected to reach agreements on greater business engagement, as well as "military enhancements" amid shared concerns about China, a senior Biden administration official said.

Marcos is due in the United States on Sunday for a four-day visit that Philippine officials say is aimed at reaffirming the special relationship between Manila and Washington, which are longtime allies.

The senior U.S. administration official said it was impossible to underestimate its strategic importance of the Philippines, although the relationship was more than just about security.