Maryland state senate passes gay marriage bill

A bill that will legalise gay marriage in the US state of Maryland has been approved in the state Senate, less than a week after it passed the state House.

The bill, which will become law when signed by Governor Martin O'Malley, who sponsored it, will make Maryland the eighth US state to permit gay marriage.

However, opponents have vowed to challenge the measure by putting it on the state ballot in November's election.

Republican New Jersey Governor Chris Christie vetoed such a bill last week.