Romney calls for rivals to concede

Mitt Romney faces an important test in Illinois tonight, with the former Massachusetts governor pinning his hopes on a win in the latest round of the Republicans' presidential nominating contest.

While he is leading, the deeply conservative Rick Santorum has caught the imagination of the party's right wing and turned the nomination battle into an extended fight before the November election against President Barack Obama.

After walloping Mr Santorum in Sunday's primary in Puerto Rico, Mr Romney has been intensifying calls for his opponents to concede defeat even before Illinois voters cast their ballots.