European Shares Set for Negative Open on Tariff Fears, Iran Tensions

European futures data pointed to a broadly negative open for shares listed in the region on Wednesday, as investors weighed U.S. proposals for sweeping new tariffs on 60 countries.

The Office of the U.S. Trade Representative has floated additional tariffs of up to 12.5% on 60 trading partners over their alleged failure to ban goods made with forced labor. The economies in line to be targeted by the measures include China, the European Union and Japan.

"The failure of our most important trading partners to address the importation of goods made with forced labor is unacceptable. This creates a dynamic where American workers are forced to compete globally on an unlevel playing field," said U.S. Trade Representative Jamieson Greer.

Investors are also continuing to monitor developments in the U.S.-Iran war after tensions escalated overnight, with Washington accusing Tehran of launching fresh attacks despite a ceasefire remaining in place.

In corporate news, Zara owner Inditex updated investors on its fiscal first-quarter earnings on Wednesday.

Sales at the Spanish retail group grew 5.8% from the previous year, coming in at 8.7 billion euros ($10.1 billion) to meet analysts' expectations. Net profit jumped 5.4% year-on-year to reach 1.38 billion euros, in line with estimates.

Economic data due today includes a Spanish PMI print, Russian unemployment and business confidence figures, and Austrian GDP data.

— CNBC's Anniek Bao contributed to this report.