UNITED NATIONS, March 20 (Reuters) - Experts with an international chemical weapons watchdog were sent to Britain following an attack on a former Russian spy in Salisbury, and the results of the analysis will take about three weeks, the agency's head said on Tuesday.

"Upon the request of the British government, the OPCW has deployed some experts to the UK and they will collect some samples," Ahmet Uzumcu, director general of the Organization for the Prohibition of Chemical Weapons, told a news briefing at the United Nations.

Asked about indications of the origin or type of substance used in the March 4 attack on Sergei Skripal and the former Russian spy's daughter in the English city, he said he "cannot project the outcome of such technical work."

Uzumcu added that results of the analysis will take "three weeks ahead at least." (Reporting by Rodrigo Campos; Editing by Jonathan Oatis)

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