By Ros Krasny and Christine Stebbins
WASHINGTON, Feb 22 (Reuters) - WhatsApp, the rapidly expanding mobile messaging app, suffered an outage for more than three hours on Saturday, frustrating users just days after its acquisition by Facebook for $19 billion.
"WhatsApp service has been restored. We are so sorry for the downtime...," WhatsApp tweeted to its more than 1 million Twitter followers on Saturday around 5:48 p.m. EST (2248 GMT).
Earlier, the service had said it was "experiencing server issues" without providing further details. Facebook referred questions on the outage to WhatsApp representatives, who did not immediately respond.
Five-year-old WhatsApp currently has about 450 million users globally and has been adding a million users daily.
On Saturday, some of those users took to other forms of social media, including blogs and Twitter to report the outage and vent their frustration.
WhatsApp is the leader among a wave of smartphone-based messaging apps that are now sweeping across North America, Asia and Europe, and is known to appeal to teens and others who avoid mainstream social networks.
During the outage the buzz on Twitter ranged from the conspiratorial - that Facebook had really bought WhatsApp to shut it down and funnel users to Facebook Chat - to the philosophical.
"So now that #Whatsapp isn't working I've actually talked to my family, they seem like nice people," tweeted @Ali_Hilu, a self-described social media addict in Jordan.
And @Iamhollybrown of Surrey, England, scolded, "Can't believe all these people are crying about Whatsapp not working, do some exercise, do some work, learn a language."