May 1 (Reuters) - The U.S. Federal Trade Commission is

set to decide whether to sue to block Exxon Mobil's ( XOM ) $60

billion acquisition of Pioneer Natural Resources ( PXD ) in the

coming days, Bloomberg News reported on Wednesday, citing people

familiar with the matter.

Exxon complied with FTC's second request for information at

the beginning of April, triggering a 30-day period within which

the antitrust agency must make a decision, the report added.

The timeline could be extended if regulators and Exxon agree

to continue working on ironing out competition issues, the

report said.

Exxon had said last week that the deal is expected to

close in the second-quarter.

The FTC had sent a second request to both the companies last

year. It had also sought additional information from Chevron ( CVX )

and Hess as well as Endeavor and Diamondback

Energy ( FANG ) related to their respective mergers.

Exxon and Pioneer did not immediately respond to Reuters

requests for comment, while the FTC declined to comment.

Antitrust experts said in October that despite the size

of the proposed Exxon-Pioneer deal, the FTC would struggle to

stop it because it is a merger of producers rather than refiners

or retail outlets.