The F-16 deal is highly controversial because China fiercely opposes all arms sales to Taiwan, which it regards as a renegade province, but has specifically objected to advanced fighter jets. The notification also comes as US trade talks with China are stalled and amid unrest in Hong Kong that many fear could prompt Beijing to move militarily against the former British colony.The State Department, which would ultimately authorize the sale, declined to comment, but members of Congress from both parties welcomed the proposal.