Gays and lesbians across the United States erupted in celebration Wednesday after the Supreme Court passed two landmark rulings on same-sex marriage in their favor.

In San Francisco, which has one of the biggest gay communities in the country, more than 400 people had gathered at City Hall for the early morning decisions broadcast from Washington, DC.

Dressed in a full-length white wedding dress, Jenni Chang kissed her partner of five years Lisa Dazols when the rulings -- which include lifting a same-sex marriage ban in California -- were announced.

"We'll get married now. We're going today. It feels amazing that our government supports us," said Dazols, wearing a purple tie and black vest and slacks.

"We'll pay more taxes, but that's okay," added Chang.

When the first ruling was announced, on the 1996 Defense of Marriage Act, the crowds exploded in cheers, stamped their feet and couples threw their arms up in the air together.

"It feels good to see love triumph over ignorance, and that began here in San Francisco," said city mayor Ed Lee.

The celebrations echoed those among an estimated 1,000 supporters of same-sex marriage who gathered under brilliant sunshine outside the high court in Washington, DC for the historic rulings.

Washington lawyer Alex Kaplan, 33, kissed his 45-year-old French partner Olivier Basdevant when the DOMA ruling was announced. "It's a dream come true -- it will have a profound effect on our family," said Kaplan.

Basdevant said the ruling will allow Kaplan to sponsor him for a US green card to stay in country permanently. "We'll be able to adopt kids and provide all the stability we need in life," he said.

Amanda Werner, a 24-year-old bisexual law student, said she came from California to Washington for the ruling. "To see it dismissed is a great feeling. It is such a great outcome for us. It was time," she said.

There was a more muted initial response in San Francisco to the Supreme Court's ruling on Proposition 8, a 2008 California ballot initiative that saw the nation's most populous state ban same-sex marriage.

Although it opens the door for gay couples to wed in the western state, it does not put an end to litigation.

The Prop 8 decision means that the legal fight will likely return to the courts in California. "You always hope there'll be a large sweep, but we knew this would be a long fight," said Dazols.

California governor Jerry Brown ordered local officials to resume issuing marriage licenses to gay couples as soon as possible -- but this may take at least 25 days, according to the LA Times.

"After years of struggle, the US Supreme Court today has made same-sex marriage a reality in California," he said, adding that gay couples will only be able to marry once the stay of a lower court injunction is lifted.

Los Angeles Mayor Antonio Villaraigosa also praised the rulings, saying: "Today we have taken another momentous step on the path to full equality and dignity for all Californians and all Americans."

"With the court's decision on Prop 8, California is poised to become the 13th state in America with full marriage equality.

"Today we celebrate a victory for love and fairness, a victory for same-sex couples who only want to follow their hearts and marry the person they love."

Online search giant Google also got in on the celebrations: typing "gay" into its ubiquitous search window produced a rainbow-colored box, a symbol of sexual diversity.