WASHINGTON — The Obama administration took the unusual step Friday of asking the Supreme Court to stop Texas from executing a Mexican citizen convicted of raping and killing a 16-year-old girl.

The administration said the court should delay the planned July 7 execution of Humberto Leal for up to six months to give Congress time to consider legislation that would directly affect Leal's case.

The 38-year-old native of Monterrey, Mexico, wasn't told he could contact the Mexican consulate after his arrest for the murder of Adria Sauceda. His lawyers say police violated an international treaty by not telling Leal he could have consular assistance.

Legislation pending in the Senate would allow federal courts to review cases of condemned foreign nationals to determine if the lack of consular help made a significant difference in the outcome of their cases. Last week, a federal judge refused to delay the execution.

The Supreme Court has previously ruled that states can't be forced to comply with the provisions of treaties without some intervening federal legislation.