US and European negotiators opened a new round of talks on creating a transatlantic free trade zone Monday amid rising political and public resistance to the deal on both sides. The fifth round of negotiations on the Transatlantic Trade and Investment Partnership (TTIP) will cover the details of proposals from the US and EU sides, with no aim to resolve the most difficult divisions between the two sides, officials said. "This is clearly not the stage in which the difficult political decisions need to be taken," an EU official said ahead of the talks. Issues still creating tensions include whether financial services should be covered in the pact, how farm product and food trade is regulated, and public procurement rules which allow local authorities to discriminate against outside suppliers to support local businesses. Another challenge is a dispute resolution mechanism for cross-Atlantic investors which activists worry could exclude the local public's interests. TTIP could eventually establish the world's largest free trade and investment zone, covering some 820 million people and more than $1 trillion in annual two-way trade But the negotiations have moved slowly amid some significant divisions, and are not expected to be completed by the original deadline of late this year. Public resistance has risen as well. Hundreds were arrested, including three politicians, in an anti-TTIP protest last week in Brussels. And resistance has surfaced in US President Barack Obama's own Democratic Party, with legislators worried that supporting the deal, which critics say could be too business-friendly, could hurt them in November elections. The Washington round of talks will run May 19-23, and on Wednesday the two sides will host a public forum to update businesses, citizens groups and others with a stake in the pact.