* Arrests over coup reach 32,000
* U.S. about to respond to extradition request - minister
* Ankara watching U.S. prosecution of gold dealer (Adds quotes, details on U.S. prosecution)
ANKARA, Sept 28 (Reuters) - Turkey may have to build new courthouses to cope with thousands of prosecutions over July's failed coup, Justice Minister Bekir Bozdag said on Wednesday, as the number of people arrested reached 32,000.
Authorities have detained or sacked people from across local government, the military, the media and the judiciary, and asked the United States to deport Pennsylvania-based cleric Fethullah Gulen, accusing him of organising the aborted uprising.
Gulen, a former ally of President Tayyip Erdogan now branded a terrorist by Ankara, denies any involvement in the uprising which killed more than 240 people as rogue soldiers commandeered fighter jets, helicopters and tanks.
One new court room was already under construction in the town of Sincan, near the capital Ankara, Bozdag told private broadcaster NTV.
"We will build new courthouses as needed ... Some defendants be prosecuted for membership in a terror organisation," he added.
He did not expect mass trials with "thousands of defendants" and added that some of the 32,000 people in custody over suspected links to Gulen could be freed as the legal process advanced.
U.S. officials have promised to respond to the extradition request for Gulen in a couple of days, Bozdag said in comments broadcast live, adding that he would seek a meeting at the U.S. Department of Justice this week.
Washington has said it is cooperating with Ankara and asked its NATO ally for patience as it processes the extradition request for the 75-year-old preacher.
Turkey is closely tracking the U.S. prosecution of a Turkish gold trader with alleged links to Erdogan, Bozdag said.
Businessman Reza Zarrab, 33, was arrested in Miami in March, then charged with helping Iran process millions of dollars in transactions that violated U.S. sanctions against Tehran in effect at the time. Zarrab has pleaded not guilty.
"As Turkey, we will remain opposed to this legal process that is being taken against us," Bozdag said.
Erdogan said at the weekend U.S. prosecutors were trying to implicate him in the case and accused U.S. officials involved in the prosecution of links to the Gulen movement.
A successful overthrow of Erdogan, who has run the country of about 80 million people since 2003, could have sent Turkey spiraling into conflict. (Reporting by Ayla Jean Yackley and Tuvan Gumrukcu; Editing by Daren Butler and Andrew Heavens)
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