Vince Gray was sworn in as the District of Columbia's sixth elected mayor just before noon Sunday, and immediately returned to the theme he has been preaching since his victory in September's primary: unity.

"Today, we begin a new chapter in the history of our city, one defined by a sense of common purpose, shared sacrifice, and communities united," Gray said. "A chapter written not by a single author, but by the pens of 600,000 residents from all eight wards and all walks of life, committed to a vision of one city, our city."

Gray has promised to unite a city whose deep divide became apparent during the Democratic primary when wealthy, white residents strongly supported the re-election of Mayor Adrian Fenty. The city's poorer, black residents voted heavily for Gray.

Gray believes he can create "One City" by creating jobs for residents of the District's poorest areas, where unemployment has climbed as high as 30 percent.

In his inaugural address, Gray channeled John F. Kennedy in his message of collaboration and "collective community." Said Gray: "Now is the time for all District residents to make the sacrifices needed to weather the storm we face, and to ask not what our city can do for you, but what can you do for your city."

The city’s new mayor also discussed the challenges D.C. faces going forward. Gray said he will immediately start planning for how the city will handle an expected $480 million budget shortfall in the next fiscal year. Although he came out strongly against using a tax hike last month to fix a $188 million gap for current fiscal year, Gray said on Sunday during a news conference following his swearing in that raising taxes isn’t out of the question for the fiscal year that starts Oct. 1, 2011.

Raising taxes, Gray said, “is getting close to [being on] the table.” He added, “we have to consider all options.”

But despite the city’s dire financial situation, Gray reiterated during his inauguration speech that unity will overcome all obstacles.

“There is no question in my mind that our challenges can and will be met if we all come together to make that happen,” he said.