China is balking at stopping and searching North Korean ships for banned weapons and materials, creating tension with Washington over UN Security Council sanctions for the North's nuclear test.
Beijing fears that such searches might trigger military clashes, and that the US may use them to police wider shipping, analysts said Tuesday.
"If intelligence can prove the ships are loaded with dangerous material, I don't think Beijing would be opposed to stopping them," said Zhu Feng, a professor at Peking University's School of International Relations. "But we just worry that the United States will abuse its naval power."
China says the resolution does not obligate it to interdict ships.
The issue will likely be high on the agenda when U.S. Secretary of State Condoleezza Rice visits Beijing this week.