UPDATE 1-Obama seeks to quell pastor controversy in speech

(Adds detail about Wright)

By Caren Bohan

PHILADELPHIA, March 18 (Reuters) - U.S. presidential candidate Barack Obama will seek to quell a controversy over inflammatory rhetoric by his former pastor in a speech on Tuesday on the issue of race.

Flare-ups over race have roiled the campaign trail as Obama, who would become the first black U.S. president, battles for the Democratic nomination with fellow Sen. Hillary Clinton, who would be the first woman president.

Obama said the controversies have become a distraction to his campaign as he vies to become the nominee to face Republican U.S. Sen. John McCain in November.

An aide to Obama, whose speech will be delivered at a historic building across from Philadelphia's Liberty Bell at 10:15 a.m. EDT (1415 GMT), said the speech will have a strong personal element. Obama worked late into the night on Sunday drafting it.

Of particular concern is the uproar over comments by Rev. Jeremiah Wright, who served as the pastor at the Chicago church where the Illinois senator was a member for 20 years.

In sermons widely circulated in the media, Wright has called the Sept. 11, 2001, attacks retribution for U.S. foreign policy, cited the U.S. government as the source of the AIDS virus, and railed against a racist America.

Wright recently retired from his role as pastor of Trinity United Church of Christ on Chicago's South Side.