China’s aluminium makers are expected to step up exports in coming months as a healthier global manufacturing climate and declining world stockpiles boost demand, traders and analysts said.

Higher exports of semi-manufactured aluminium could dampen London Metal Exchange (LME) aluminium prices, which have surged nearly 14 percent this year, as well as stoke global trade tensions.

China accounts for more than half of world aluminium output.Chinese semis exports fell last year after prices slumped in late 2015 to decade lows. Production rebounded more than 20 percent for the first two months of 2017, according to BOFA Merrill Lynch, while exports stabilised but have yet to catch up, official data showed.

“China’s exports are getting back to normal. Calendar 2016 was slow in terms of China exports. The Western world has been and is rationalizing, stocks are drawing down,” said a source at a global trading house.

China will release trade data for April on Thursday.

LME aluminium prices have surged at double the rate of Shanghai Futures Exchange (SHfe) prices this year reflecting the decline in stockpiles, to log the biggest advance among the base metals.Prices last month hit $1,981 a tonne, the highest since late 2014.

“A lift in semi-manufactured exports is obviously bearish for LME prices which are likely to head lower in the next few months,” said analyst Dan Morgan at UBS in Sydney.However, he forecast a recovery in prices at the end of the year as China curbed domestic production.“Our base case is that there will be constraints of some sort in China,” Morgan said.