BEIJING (AP) — A survey shows China's manufacturing activity improved in August but sales weakened amid a worsening tariff war with Washington.

An industry group, the China Federation of Logistics & Purchasing, said Friday its monthly purchasing managers' index rose to 51.3 on a 100-point scale from July's 51.2.

Components for new orders and exports declined, suggesting demand is weakening.

Citigroup economists said in a report "the trade war's impact increasingly appeared in the data."

Washington and Beijing have imposed tariff hikes on $50 billion of each other's goods. President Donald Trump is poised to impose penalties on an additional $200 billion of Chinese imports as early as next week. Beijing has said it will retaliate.