Obama's tax return shows he pays 20 per cent rate

US President Barack Obama has published his tax return, showing his income fell last year.

The forms also reveal he was taxed at a higher rate than Republican election opponent Mitt Romney in 2011, adding fuel to a Democratic effort to raise taxes on the rich.

Mr Obama pays a slightly lower rate than his own secretary, the White House said.

The President and his wife, Michelle, paid an effective tax rate of 20.5 per cent on income of $789,674 last year, the White House said, which fell by nearly $1m on the previous year.

Mr Romney has estimated he will pay a 15.4 per cent tax rate on income of $20.9m, though he has not filed his return yet.

Mr Romney is almost certain to take on Mr Obama in November's presidential poll.

The White House seized on the publication of the returns, and annual ritual, to make the case for a so-called "Buffet Rule" under which the richest Americans would not pay lower tax rates than the middle class.