President Kenyatta's deputy, William Ruto, is also being sworn in.

Among the foreign leaders expected to attend are Israeli Prime Minister Benjamin Netanyahu, Ugandan President Yoweri Museveni and Rwandan President Paul Kagame.

How are the opposition responding?

Mr Odinga has promised to hold a "memorial rally" to honour those killed during the four months of political upheaval since the August vote.

Police have warned the opposition against holding the event.

Why was there an election re-run?

Chief Justice David Maraga said the August election had not been "conducted in accordance with the constitution" and declared it "invalid, null and void".

The Supreme Court ruled that the result had been "neither transparent nor verifiable".

But Mr Odinga urged his supporters to boycott the second vote because he said no reforms had been made to the electoral commission since the original poll.

Correspondents say the election dispute has left Kenya deeply divided.

What has happened since the first vote?

Mr Kenyatta faces an uphill task in uniting a fractured nation.

About 50 people are reported to have been killed in violence since he was declared the winner in August.

Mr Odinga, who went away on a 10-day speaking tour in Europe and America after withdrawing from the election re-run, has called for a "national resistance movement" to "restore democracy".