Credit: Jason Reed-Pool/AP Photo

The U.S. visa system will now treat same-sex married couples just as it does straight couples.

Announcing the change during a visit to the U.S. embassy in London on Friday, Secretary of State John Kerry said the State Department was "tearing down an unjust and an unfair barrier that for too long stood in the way of same-sex families being able to travel as a family to the United States."

The announcement came in response to the Supreme Court's landmark decision striking down the Defense of Marriage Act (DOMA). In June, the Court ruled 5-4 to end the federal ban on same-sex marriage and extend federal benefits to married gay couples.

Homeland Security Secretary Janet Napolitano had already announced as much last month, saying visas for gay couples would be processed "in the same manner as those filed on behalf of an opposite-sex spouse," hours after the Supreme Court handed down its ruling.

For U.S. citizens in same-sex marriages, their foreign spouses will now enjoy easier access to U.S. visas. The same preferential treatment will apply, as it does to straight husbands and wives who seek spousal visas.

For gay foreigners seeking entry to the U.S., it means easier visa access for their spouses. Same-sex husbands and wives will now be eligible for preferential visas to accompany their spouses.

"If you are the spouse of a U.S. citizen, your visa application will be treated equally," Kerry said. "If you are the spouse of a non-citizen, your visa application will be treated equally."

Visas for gay couples had become a political issue in the push for immigration reform, as debate had emerged this year over how to treat married gay couples under any new legislation. The Supreme Court's decision, along with the State Department's ruling, removed some pressure from immigration-reform advocates by answering that question.

To apply for spousal visas, however, gay couples will have to be legally married; domestic partnerships and civil unions won't count. But gay couples can be married in any jurisdiction where their marriage is legally recognized.

For instance, a couple legally married in their home state or province can apply as married, even if their home country does not recognize gay marriage at a federal level. For couples who live in countries and states where gay marriage is not recognized, they can be married in other countries that do recognize gay marriage, and the State Department will recognize them as married couples.

For gay Americans who are engaged but cannot legally marry, their partners can apply for fiancé visas to travel to the U.S. for the purpose of marrying.

Kerry said the changes will take effect immediately.