U.S. Republican presidential candidate Mitt Romney has swept primary elections in three more states, moving him even closer to becoming the nominee to run against President Barack Obama in November.

Romney now has more than 900 delegates, after wins Tuesday in Indiana, North Carolina and West Virginia. The former Massachusetts governor needs 1,144 delegates to clinch his party's nomination and earn the chance to face the Democratic incumbent.

In the Indiana primary, Republican U.S. Senator Richard Lugar lost his bid to run for re-election in the state he has represented for more than three decades. The 80-year-old incumbent was defeated in a tough battle against a candidate backed by the Tea Party movement, which supports smaller government and less taxes.

In a statement, President Obama recognized Senator Lugar for his distinguished service and praised his work across party lines and in efforts to secure the world's most dangerous weapons. President Obama said the senator “comes from a tradition of strong, bipartisan leadership on national security that helped us prevail in the Cold War and sustain American leadership ever since.”

In North Carolina, voters approved a state constitutional amendment defining marriage as the union between a man and a woman. North Carolina law already bans homosexual marriage.

President Obama Tuesday made his case for Congress to advance bills he says will boost the economy, such as helping veterans find jobs, assisting homeowners in getting a lower mortgage rate, and extending tax credits to producers of alternative forms of energy and small businesses that create jobs.

Speaking at a university in Albany, New York, the president said progress is being made, including with hundreds of thousands of jobs created each month over the last several months. But he told the audience, “everybody knows we need to do more. And in order to do that, we are going to need some more action from Congress. Democrats and Republicans have to come together.”