The family say she has been stopped because of the US travel ban on several countries.
The Chinese President, Xi Jinping, has marked the 40th anniversary of the opening up of the country's economy with a warning that no-one can dictate to China what it should or shouldn't do.
The mother of a dying boy in California is being prevented from seeing him because of a US ban on visitors from Yemen, the family says.
A new US report into the extent of alleged Russian social media meddling in the US.
