The airstrikes were prompted by intelligence indicating a likely Islamic State attack. The US said a deal has been reached with Turkey to use a key airbase.
But nine other tourists arrested in Inner Mongolia on a 47-day visit to ancient sites are being held on charges of 'criminal wrongdoing.' Those due to be released are from South Africa and Britain.
The country's president says additional police an military powers are needed to tamp down militants, who have carried out two mass casualty attacks on tourist sites in the past 4 months.
The fighting marks the most intense rebel attack in three years in the bitterly contested city.