WASHINGTON: Facebook or Twitter may have helped unite many people across the globe, but a survey has revealed that one in five divorces in the US now involve the popular social networking sites.

According to the survey by the American Academy of Matrimonial Lawyers, a staggering 80 per cent of divorce lawyers have also reported a spike in the number of cases that use social media for evidence of cheating.

Flirty messages and photographs found on Facebook are increasingly being cited as proof of unreasonable behaviour or irreconcilable differences. Many cases revolve around social media users who get back in touch with old flames they hadn't heard from in many years, the Daily Mail reported.

Facebook was by far the biggest offender, with 66 per cent of lawyers citing it as the primary source of evidence in a divorce case. MySpace followed with 15 per cent, Twitter at 5 per cent and other choices lumped together at 14 per cent, the survey has found.

The survey reflects the findings of a UK law firm last year showing that 20 per cent of its divorce petitions blamed Facebook flings.

"The most common reason seemed to be people having inappropriate sexual chats with people they were not supposed to," Mark Keenan, the Managing Director of Divorce-Online, was quoted by the British newspaper as saying.

'Desperate Housewives' star Eva Longoria recently split from her basketball player husband Tony Parker after alleging that he strayed with a woman he kept in touch with on Facebook.