China's stock markets extended losses on Tuesday, with investors concerned over slowing growth at home and the US set to impose fresh tariffs on $200 billion worth of Chinese imports as early as this week.

At the mid-day break, the Shanghai Composite index was down 1.55 points or 0.1 per cent at 2,719.19, extending losses from five consecutive negative sessions.

China's blue-chip CSI300 index was down 0.16 per cent, with its financial sector sub-index lower by 0.17 per cent, the consumer staples sector down 0.13 per cent, the real estate index down 0.37 per cent and the healthcare sub-index down 0.73 per cent.

Chinese H-shares listed in Hong Kong fell 0.21 per cent to 10,790.65, while the Hang Seng Index was flat at 27,721.21.

China had reported another outbreak of deadly African swine fever late on Monday, its third new case in two days, as the highly contagious disease spreads rapidly through the world's top pork producer.

Manufacturing activity took a hit from weak orders in August, surveys showed, a sign firms are feeling the pinch from an intensifying trade war between the United States and China that could derail global growth.

Shenzhen-listed shares of construction equipment maker Zoomlion were flat after hitting more-than-nine-year lows on Monday after posting a 23.6 per cent drop in first-half profit. The smaller Shenzhen index was unchanged for the day and the start-up board ChiNext Composite index was weaker by 0.55 per cent.

Around the region, MSCI's Asia ex-Japan stock index was weaker by 0.26 per cent, while Japan's Nikkei index was down 0.14 per cent . The yuan was quoted at 6.8221 per U.S. dollar, 0.02 per cent firmer than the previous close of 6.8235.

The largest percentage gainers in the main Shanghai Composite index were Ningxia Xinri Hengli Steel Wire Rope Co Ltd , up 10.06 per cent, followed by ADD Industry Zhejiang Co Ltd, gaining 10.02 per cent and Milkyway Chemical Supply Chain Service Co Ltd, up by 10.01 per cent.

The largest percentage losses in the Shanghai index were Yifeng Pharmacy Chain Co Ltd, down 5.35 per cent, followed by Harbin Gong Da High-Tech Enterprise Development Co Ltd, losing 5.03 per cent and LBX Pharmacy Chain JSC, down by 4.33 per cent.

So far this year, the Shanghai stock index is down 17.73 per cent, while China's H-share index is down 7.6 per cent. Shanghai stocks have declined 0.17 per cent this month. Top gainers among H-shares were China Gas Holdings Ltd, up 2.04 per cent, followed by China Vanke Co Ltd, gaining 1.34 per cent and Tencent Holdings Ltd, up by 1.27 per cent.

The three biggest H-shares percentage decliners were New China Life Insurance Co Ltd, which has fallen 2.55 per cent, Huatai Securities Co Ltd, down 1.6 per cent and Shenzhou International Group Holdings Ltd, down by 1.6 per cent.

About 4.89 billion shares have traded so far on the Shanghai exchange, roughly 37.6 per cent of the market's 30-day moving average of 13.02 billion shares a day. The volume traded was 10.22 billion as of the last full trading day.

As of 04:15 GMT, China's A-shares were trading at a premium of 18.28 per cent over the Hong Kong-listed H-shares. The Shanghai stock index is below its 50-day moving average and below its 200-day moving average.

The price-to-earnings ratio of the Shanghai index was 11.49 as of the last full trading day, while the dividend yield was 2.7 per cent. So far this week, the market capitalisation of the Shanghai stock index has fallen by 0.17 per cent to 28.97 trillion yuan.

In Hong Kong, the sub-index of the Hang Seng index tracking energy shares dipped 0.2 per cent, while the IT sector rose 1.3 per cent. Top gainer on Hang Seng was CK Asset Holdings Ltd, up 3.42 per cent, while the biggest loser was WH Group Ltd, which was down 1.48 per cent.