U.S. lawmakers looking into doping in sports Tuesday sent letters to the heads of the National Basketball Association (NBA), National Hockey League (NHL), Major League Soccer (MLS) and four other organizations asking for information about their drug-testing policies.

The House Government Reform Committee sent a similar request to the NFL last week.

"This is the compare-and-contrast phase of the investigation," David Marin was quoted by the Associated Press as saying. Marin is the spokesman for committee chairman Tom Davis.

During the panel's 11-hour hearing on steroids in Major League Baseball last month, several congressmen threatened government legislation to govern drug testing in MLB and possibly all U.S. sports.

The seven letters sent on Tuesday were addressed to NBA commissioner David Stern, NHL commissioner Gary Bettman, ATP chief executive Mark Miles, MLS commissioner Don Garber, U.S. Soccer Federation president Bob Contiguglia, USA Track & Field CEO Craig Masback, and USA Cycling CEO Gerard Bisceglia.

The officials were given an April 12 deadline for turning over copies of their sports' current and past drug-testing policies and information about how those were negotiated.

The committee also asked for information such as the number of drug tests each year, the number of positive results and which substances are tested for. The letters specified that the committee wants "summary information, and does not require identification of individual players."

The NHL does not test players for performance-enhancing drugs, while first-time offenders are suspended for five games in the NBA.

Tennis, cycling and athletics follow International Olympic Committee and World Anti-Doping Agency standards, including a two-year ban for a first offense and a lifetime ban for a second offense.

Source: Xinhua