WASHINGTON (AP) - The United States Supreme Court is indicating it could strike down the federal law that prevents legally married gay couples from receiving a range of federal benefits for married people.

Justice Anthony Kennedy, often the decisive vote in close cases, joined the four more liberal justices in raising questions about the provision of the federal Defence of Marriage Act that is being challenged at the Supreme Court.

Justice Kennedy said the law appears to intrude on the power of states that have chosen to recognize same-sex marriages. Other justices said the law creates two classes of marriages.

The law affects a range of benefits available to married couples, including tax breaks, survivor benefits and health insurance for spouses of federal employees.