(Adds auto industry group statement, details on tariff impact)

By David Shepardson

WASHINGTON, May 15 (Reuters) - U.S. President Donald Trump is expected to delay a decision on imposing tariffs on imported cars and parts by up to six months, three Trump administration officials told Reuters, , avoiding opening yet another front in his global trade battles.

A formal announcement is expected by Saturday, the due date for Trump to make a decision on recommendations by the Commerce Department to protect the U.S. auto industry from imports on national security grounds, the officials said.

A White House spokesman declined to comment.

They added that the administration has drafted language to formally delay a decision on the tariffs that is due by May 18.

Reuters reported last week that automakers expected Trump to delay the decision as trade negotiations get underway with the European Union and Japan.

General Motors Co, Volkswagen AG, Toyota Motor Corp and others have warned of the damaging impacts of imposing tariffs of up to 25 percent on imported cars and parts.

The White House has held a series of high-level meetings on the issue in recent days, and administration officials have repeatedly told automakers they planned to delay the decision.

In February, the Commerce Department submitted its "Section 232" national security report to the White House. The agency was investigating whether imports harmed U.S. national security by weakening American automakers' ability to invest in future technologies. The Commerce Department's specific recommendations have not been revealed.

A series of announcements by GM last week of $700 million in investments in three Ohio plants and efforts to sell the company's closed Lordstown plant had made Trump more inclined to delay the tariffs, administration officials told Reuters last week.

At the same time, Trump has escalated his trade war with China, sharply increasing tariffs on $200 billion worth of Chinese goods and launching public consultations on remaining Chinese imports of about $300 billion.

The auto tariffs face wide opposition in Congress. The White House has refused to turn over the Commerce Department report to Republican Senator Chuck Grassley, chairman of the Senate Finance Committee, who has been demanding to see it.

Last week, 159 House of Representatives members led by Ways and Means Committee Vice Chair Terri Sewell wrote White House National Economic Council Director Larry Kudlow to urge him to advise Trump against “imposing trade restrictions that could harm the auto sector and the American economy.”