Washington, Dec 14 (DPA) A federal judge Monday tossed out a key provision of President Barack Obama's health care plan that requires people to have insurance.

Judge Henry Hudson of the US District Court in Richmond, Virgina, found the mandate for all citizens to carry health insurance violated the US Constitution's limits on Congress' ability to regulate commerce.

The decision comes as part of a legal challenge to the law by the state of Virginia's Attorney General Ken Cuccinelli, which was among dozens of lawsuits contesting the law. Monday's ruling was the first time an element of the bill has been struck down.

Legal analysts expect the Virginia lawsuit and other cases to wind through the appellate courts, probably reaching the US Supreme Court.

The health care overhaul was a key element of Obama's domestic agenda, and he signed it into law in March after months of debate on the issue in Congress.

The dramatic overhaul of the country's health insurance system aims to provide nearly all Americans with access to at least some form of health insurance while imposing new regulations on insurance companies. It constitutes the most comprehensive changes to the US health sector in four decades.

But the effort was contentious, and the issue was used as a key campaign plank by Republicans in November congressional elections, which saw the party regain control of the lower House of Representatives and trim the Democratic majority in the Senate.