China on Tuesday returned a U.S. naval drone seized in the South China Sea last week, a peaceful resolution to a military standoff that threatened to inflame maritime tensions ahead of president-elect Donald Trump’s inauguration.

The Chinese Ministry of Defense said in statement that after “friendly negotiation” the drone was transferred to the U.S. In a separate statement, the Pentagon confirmed the drone’s return, but offered a less friendly-sounding account.

The incident was “inconsistent with both international law and standards of professionalism for conduct between navies at sea,” the Pentagon statement said.

“The U.S. has addressed those facts with the Chinese through the appropriate diplomatic and military channels, and have called on Chinese authorities to comply with their obligations under international law and to refrain from further efforts to impede lawful U.S. activities,” the statement said.