"Dr Buthaina Shaaban visited Oslo on June 18th and 19th at the invitation of the Norwegian foreign ministry to take part in a conference," one of her colleagues told AFP. "It was the first trip to Europe by a top official since the beginning of the crisis," he said.
Anti-regime protests that began in March 2011 later became an armed rebellion after a crackdown on dissent. More than 162,000 people are estimated to have been killed since, and millions more have been displaced from their homes.
The European Union, of which Norway is not a member, has imposed a wave of sanctions on Syria, including drawing up a blacklist of officials, of whom Shaaban is one.
Her office said that while in Oslo she met Norwegian Foreign Minister Borge Brende, former US president Jimmy Carter, UN Under Secretary General for Political Affairs Jeffrey Feltman and the head of Iranian President Hassan Rouhani's office.
On June 16th she had visited Moscow for talks with Russia's deputy Foreign Minister, Mikhail Bogdanov. Both Iran and Russia are key allies of Assad's regime.