Washington, Jan 13 (IANS): Secretary of State John F. Kerry began his farewell tour in Vietnam on Friday, in a push to Washington's 'Asia pivot', as the top US diplomat prepares to leave office on January 20.

He arrived in Vietnam on Thursday for his fourth and final visit.

Even as his nominated successor, Rex Tillerson, was answering questions at his confirmation hearing on Wednesday, Kerry was already in the air for the 22-hour journey from Washington to Southeast Asia, The Washington Post reported.

It is the final trip overseas for the most travelled Secretary of State in US history.

With his latest flight, he has now logged more than 1.4 million miles, sources said.

His Vietnam visit will conclude on Saturday in Ca Mau, the country's southernmost province, in the Mekong river delta, where Kerry served as a marine during the Vietnam war, Efe news reported.

Kerry will also hold talks with experts on environmental problems affecting the region - one of the planet's most-affected areas due to climate change - and measures to help Vietnam develop clean energies and sustainable infrastructures.

The Secretary of State is scheduled to leave for Paris on Saturday to confer with other foreign ministers on Middle East peace and then to London to meet UK Foreign Secretary Boris Johnson.

He will end his tour at the World Economic Forum in Switzerland on January 17 and 18, and will hand over charge to Tillerson on January 20, when Donald Trump is sworn in as the new US President.