By Jody Godoy

NEW YORK (Reuters) -The U.S. Federal Trade Commission allowed Chevron's $53 billion purchase of Hess Corp on Monday, in an order that barred Hess CEO John Hess from Chevron's board.

The FTC's order leaves Exxon Mobil's challenge to the deal, which is expected to stretch deep into next year, as its final hurdle.

The proposed merger included a Chevron board seat for Hess when it was first announced last October, and the FTC sent a second information request to Chevron two months later.

Chevron Chairman and CEO Mike Wirth welcomed the completion of the FTC's review on Monday, but called it unfortunate that John Hess would not be allowed to join the board.

"I have the utmost respect for John, the company he has built, and the contributions he has made to our industry," he said.

The FTC alleged that Hess -- the son of Hess Corp founder Leon Hess -- had communicated publicly and privately with members of the Organization of the Petroleum Exporting Countries (OPEC) group of oil producers, and encouraged high-level representatives of the group "in their stated mission to stabilize global oil markets."

Allowing him to join Chevron's board "would amplify Mr. Hess's supportive messaging to OPEC and others, thereby meaningfully increasing the likelihood that Chevron would align its production with OPEC's output decisions to maintain higher prices," the FTC said.

Hess' board believes the claims are meritless, the company said in a statement.

"Mr. Hess' public and private communications with OPEC officials were consistent with his communications with U.S. government officials, the International Energy Agency and global business leaders on what will be needed to ensure an affordable and orderly energy transition," the company said.

The allegations are similar to the FTC's claims against former Pioneer Natural Resources CEO Scott Sheffield, who was barred from joining Exxon Mobil's board when the FTC reviewed its $60 billion acquisition of Pioneer.

Sheffield has sought to have the claims withdrawn.

The two cases are "an important step towards ensuring that U.S. oil producers are serving as a competitive check on OPEC+ rather than subordinating their independent decision-making to the goals set by a cartel," FTC Chair Lina Khan and the Commission's two other Democratic members said on Monday.

The FTC's two Republican commissioners voted against the Chevron-Hess action, calling it politically motivated and lacking basis in antitrust law.