EU competition regulators have resumed their scrutiny of U.S. oil industry services group Halliburton Co's plan to acquire smaller rival Baker Hughes, a deal which U.S. authorities say is uncompetitive and wants to block.

The European Commission, which halted its investigation into the $35 billion deal last month while waiting for more details from the companies, will now decide by Aug. 11 whether to clear or veto the takeover.

"Once the requested missing information is provided the Commission restarts the clock," Commission spokesman Ricardo Cardoso said in an email.

The EU antitrust authority has previously expressed concerns that the deal may reduce competition and innovation.

Halliburton has said it is willing to sell assets from both companies with a combined 2013 revenue of $5.2 billion but has yet to make a formal offer to regulators.

The U.S. Justice Department filed a lawsuit last week to stop the merger, valued at $35 billion when it was first announced in November 2014, saying it would leave only two dominant suppliers in 20 business lines in the global well drilling and oil industry construction services industry, with Schlumberger NV being one of the two.