New York will become the sixth and most populous state to allow gay marriage. State senators voted 33-29 to approve the marriage equality legislation introduced by Governor Andrew Cuomo, a Democrat in his first year of office.

"New York has finally torn down the barrier that prevented same-sex couples from exercising the freedom to marry and from receiving the fundamental protections that so many couples and families take for granted," Cuomo said in a statement.

After Cuomo signs the bill into law, same-sex weddings can start taking place in New York in 30 days, though religious institutions and nonprofit groups with religious affiliations will not be compelled to officiate at such ceremonies.

Cheers erupted in the Senate gallery in the state capital Albany and among a crowd of several hundred people who gathered outside New York City's Stonewall Inn, where riots following a police raid in 1969 sparked the modern gay rights movement.

New York City Mayor Michael Bloomberg, an advocate for gay marriage who lobbied state lawmakers in recent weeks, said the vote was an "historic triumph for equality and freedom."

President Barack Obama, who attended a fundraiser in New York on June 23 for Gay Pride Week, has a nuanced stance on gay issues. Experts say he could risk alienating large portions of the electorate if he came out strongly in favor of such matters as gay marriage before the 2012 elections.

In California, a judge overturned a ban on gay marriage last year, but no weddings can take place while the decision is being appealed. It could set national policy if the case reaches the US Supreme Court.

However, gay marriage is banned in 39 states.