By Laura Trevelyan
BBC News, New York
Time is running out in the fight against poverty, says UN chief Ban Ki-Moon
The world's wealthiest countries are failing to deliver on their promises to give money to the world's poorest nations, a UN report says.
The UN report on progress towards the millennium development goals says this is threatening targets for drastically reducing world poverty by 2015.
The UN report says there has been some improvement but not enough.
World leaders signed up to ambitious goals eight years ago aimed at reducing poverty, hunger and disease by 2015.
Now the UN report says wealthy countries are not living up to the commitments they made at the Gleneagles summit in 2005 - and aid needs to be increased by $18bn a year.
Although progress has been made on debt relief for the poorest countries, assurances given on trade and development have not been honoured.
'Running out of time'
UN Secretary General Ban Ki-moon called the report a "wake up call".
"Delivery on commitments made by member states has been deficient, and has fallen behind schedule," said Mr Ban.
"We are already in the second half of our contest against poverty," he continued. "We are running out of time".
A UN official urged the US, Japan and the European Union to give the money they had already pledged.
Privately, European diplomats say the wealthy Gulf states and China could give more aid and question whether Russia's oil wealth meant it could afford more too.
World leaders will discuss the poverty reduction goals when they gather in New York for the opening of the UN General Assembly later this month.
Against a backdrop of gloomy economic news, food shortages and high fuel prices, the UN's argument that more should be done to help the world's poorest could be difficult to sell.