US PRESIDENT Barack Obama gave tentative backing to Zimbabwe’s fragile national unity government overnight, but the country’s prime minister, Morgan Tsvangirai, left a White House meeting largely empty-handed.

Mr Obama promised $US73 million ($90 million) in new aid that a White House official said later would go toward fighting HIV-AIDS and promoting good governance in the poverty-stricken southern African nation. Significantly, the money will not go to the government but will be channeled through aid agencies.

The meeting underscored the quandary Mr Obama faces – how to support Mr Tsvangirai’s efforts to rebuild Zimbabwe’s shattered economy without bolstering his rival, President Robert Mugabe. Western states accuse Mugabe of years of misrule and largely shun him.

Mr Tsvangirai, a former labor official and longtime opposition leader, was in Washington as part of a tour of Europe and the United States to rally support for the power-sharing government he formed with Mr Mugabe in February after bitterly disputed elections that saw his supporters beaten and jailed.

“We now have a power-sharing agreement that shows promise,” Mr Obama said, with Mr Tsvangirai sitting next to him in the Oval Office.

He praised Mr Tsvangirai’s efforts to tackle hyperinflation that has devastated the economy and to improve the daily lives of Zimbabweans who face chronic food shortages and an unemployment rate of about 90 per cent.

Mr Tsvangirai, whose government says it needs $US10 billion to rebuild the economy, has been trying to get funding for his cash-strapped administration and to persuade the international community to lift sanctions.

But Mr Obama made clear that while the United States was prepared to work with Tsvangirai, it would not give money directly to the unity government because of concerns about governance.

A State Department official said US humanitarian aid to Zimbabwe totaled $US150 million in the 2009 fiscal year. A White House official said the $US73 million announced by Mr Obama was new money.