*U.N. sources say final death toll could rise as high as 20
*Taliban behind attacks, reports suggest
*Demonstrators at the burnings take place across the Middle East
*One of the dead is a 53-year-old female Norwegian pilot
*Mastermind behind attacks - a known militant - arrested say Afghan police
*Afghan authorities suspect insurgents blended into protesters
*Norwegian, Romanian, Swedish and Nepalese nationals among those killed
At least seven United Nations staff were murdered - two by beheading - after extremists stormed their compound in northern Afghanistan today.
According to reports, protesters in the northern city of Mazar-i-Sharif beheaded two U.N. guards, seized their weapons and began shooting those inside the compound after a demonstration against Koran burnings in the U.S. turned violent.
Reports emerged tonight that the Taliban had claimed responsibility for the attacks, saying they were part of a campaign of violence in the run up to presidential elections.
The bloodshed is the worst attack on the U.N. in Afghanistan since the war began in 2001.
Firebrand: Pastor Terry Jones threatened to burn a koran last year and carried the threat out last month
Protest: Thousands of protectors flooded the streets of Mazar-i-Sharif chanting anti-American slogans before the violence broke out
Controversy: U.S. Pastor Terry Jones, pictured last September, gained worldwide attention after he planned to burn a Koran



