Aung San Suu Kyi, the pro-democracy campaigner who was elected to the Burmese parliament earlier this year, flew out of Yangon on Sunday ahead of her first visit to the US for two decades.

Due to arrive on Monday, the 18-day tour will be the latest round of her extraordinary return to the international stage since she was released from house arrest in 2010. It follows her visit to Europe earlier this year when she received the Nobel peace prize some 21 years after it was awarded to her.

The US trip begins in Washington where she will meet a number of senior administration officials including President Obama. She will also be bestowed with the Congressional Gold Medal, the highest honour of the US Congress.

Suu Kyi, 67, will visit Burma ex-pat communities in San Francisco and New York, where she lived for two years in the late 1960s working at the UN.

While the visit is being billed as a celebration of both Suu Kyi's life and of the opening up of Burma under the reformist government of President Thein Sein, the trip will not be without its diplomatic sensitivities.

The Burmese president is himself to make his first visit to the US later this month to attend the annual UN general assembly, and there have been suggestions that by preceding him Suu Kyi could over shadow his arrival.

There is also the delicate issue of the Rohingya Muslims in the west of the country who have been left in a state of limbo as they are unrecognized as citizens by the Burmese regime but unwelcome also in neighbouring countries. Suu Kyi has so far failed to take a strong line over their plight.

The US ban on all imports from Burma imposed in protest at the human rights abuses of the regime remains in place, but as the military junta's political grip has gradually loosened in the country Washington has responded by allowing American companies to invest in the country.