Eurozone manufacturers were at their most downbeat in almost six years in June as hopes for a speedy resolution to a series of disputes between the U.S. and its main trading partners faded.

Weaker exports have cooled the eurozone economy over the past 18 months, hitting the currency area’s manufacturing sector particularly hard. Economists partly attribute that slowdown in exports to higher global tariffs and uncertainty about how much further such levies will be raised, as well as a lack of clarity about when and in what way the U.K. will leave the European Union.

That uncertainty and the effect it is having on business confidence has been a key factor behind the European Central Bank’s shift toward considering fresh stimulus, including a cut in its already-negative interest rate and a resumption of its bond purchases, which were paused in December.

Figures released by the European Commission on Thursday showed confidence in the currency area’s industrial sector plummeted to its lowest level since September 2013 during June, while consumers experienced a less marked decline in optimism.

The Commission’s Economic Sentiment Indicator--an aggregate measure of confidence across businesses and consumers--fell to 103.3 from 105.2 in May, hitting its lowest level since August 2016.