Eventually , they invaded Balhae in 925 and the capital Sanggyeong ( also known as Holhan fortress ) fell after ten days .
The Khitans ' growing power in Manchuria was the most threatening to Balhae .
Khitans invaded Balhae in 925 and the capital Sanggyeong ( also known as Holhan fortress ) fell after ten days .
The Khitans ' growing power in Manchuria was the most threatening to Balhae .