(Adds CFTC official's comments, other background)

By Timothy Gardner and Tom Doggett

WASHINGTON, July 24 (Reuters) - The U.S. commodity futures regulator on Thursday charged a Dutch trading fund and its Chicago unit with manipulating oil markets in March 2007, an action resulting from the commission's nationwide probe into illegal energy trading.

Three employees of the global fund Optiver Holding BV, including the company's CEO and head of trading, manipulated crude oil, gasoline and heating oil futures on the New York Mercantile Exchange NMX.N, the U.S. Commodity Futures Trading Commission charged.

The defendants made about $1 million through manipulative trading conducted over the exchange's Globex electronic trading platform, according to the complaint.

The agency has been under growing pressure to crack down on any market manipulation and excessive energy market speculation amid oil prices that hit a record of more than $147 per barrel this month.

Thursday's enforcement action came a day before the Senate was scheduled to have a major vote on legislation to rein in speculation and impose new regulations on traders that the CFTC would have to enforce.

The CFTC's acting enforcement director, Stephen Obie, denied that the announcement of the case was timed to influence the vote on the bill. "This was not a politically motivated case," he said.

"BANGING THE CLOSE"