Facebook founder Mark Zuckerberg rides a buffalo during vacations in Vietnam (VIDEO | 6 PHOTOS)

Facebook website founder Mark Zuckerberg rides a water buffalo in northern resort town of Sapa in Lao Cai province, Vietnam in this picture taken.

Mark Zuckerberg may be welcome in Vietnam, even if his brainchild Facebook is not.

The Facebook founder is vacationing in the communist country that blocks its citizen from using his social networking site.

According to The Associated Press, Zuckerberg, his longtime girlfriend Priscilla Chan and a group of friends arrived in Vietnam Dec. 22. They spent Christmas Eve in popular tourist spot Ha Long Bay and Christmas Day at an ecolodge in the northern mountain town of Sapa, where Zuckerberg rode a buffalo.

Vietnamese website Tuoitre News reported that Zuckerberg, 27, and Chan have already spent about $6,000 on travelling by private helicopter.

The pair have been dating since Zuckerberg's sophomore year at Harvard, where they met at a Friday night party for Jewish fraternity Alpha Epsilon Pi. Chan, a Chinese-American from the Boston suburbs. struck up a conversation with Zuckerberg while waiting in line for the bathroom.

"He was this nerdy guy who was just a little bit out there," Chan told the New Yorker last year.

When Zuckerberg left Harvard in 2005 to focus on Facebook full time, he recruited classmates, including Chan, who, according to The Harvard Crimson newspaper, told him, "I'd love a job at facebook," before offering him a Twizzler.

These days, Chan identifies Zuckerberg as her partner on her Facebook page and, according to tech writer Sarah Lacy, she has imposed a set of rules on her steady, including, " One date per week, a minimum of a hundred minutes of alone time, not in his apartment, and definitely not at Facebook."

Priscilla Chan (R), girlfriend of Facebook's founder and chief executive Mark Zuckerberg, visits a minority village in Vietnam's northern Sapa resort town December 26, 2011. Zuckerberg and Chan toured Halong Bay last Saturday before going to Sapa during a surprise visit to Vietnam

While the couple seem to be enjoying their vacation, it's likely, given Zuckerberg's insatiable work ethic, that he's finding some time for business, namely expanding Facebook to Vietnam, where social media is growing. Though Facebook is blocked by the government's censors, locals can still access the site with relative ease, but it seems they would rather choose local offering Zing Me.

Zuckerberg, whose net worth is measured in the billions, doesn't need the money. Rather he seems motivated by his obsession to bring Facebook to one billion users worldwide.

Vietnam may block its citizens from using to Facebook, but that didn't stop website founder Mark Zuckerberg from spending his vacation there. Zuckerberg spent Christmas Eve in the popular tourist destination Ha Long Bay, local official Trinh Dang Thanh says.

Facebook's founder and chief executive Mark Zuckerberg (3rd L) walks down as he visits a minority village in Vietnam's northern Sapa resort town December 26, 2011. Zuckerberg and his girlfriend Priscilla Chan toured Halong Bay last Saturday before going to Sapa during a surprise visit to Vietnam