Image caption In Pakistan levels of mortality in children under five increased last year

The number of children dying before the age of five has fallen significantly over the past 20 years, the UN children's agency Unicef has said.

Some 6.9 million children died before the age of five last year, compared to 12 million such deaths in 1990. Almost 19,000 under-fives died daily in 2011.

Unicef said some of the reduction was due to poorer countries getting richer.

But some was also due to well-targeted aid such as encouraging breastfeeding or immunizing against common diseases.

The sharpest drops in levels of child mortality were in countries that had received a lot of external assistance.

Analysis Unicef is keen to stress that the cuts in child mortality show that foreign aid works. That is what you would expect from an aid agency that is competing for scarce donor funds with so many others in the aid industry marketplace. But reducing deaths in young children really is an area where simple, cheap interventions can make a huge difference. Inoculating children against common diseases like measles - or providing basic health clinics for pregnant women - is usually uncontroversial. And in my experience of working in developing countries over many years it really can work. Much larger sums are spent by rich-country governments on less immediately appealing areas. Millions of dollars are spent every day on "capacity building" or "security sector reform". That can sometimes work too; a fragile post-war state without a decent police force is unlikely to have sustainable economic growth But men in suits holding meetings about rebuilding shattered states will never have the same appeal for donors as nurses inoculating babies.

"If you look at the countries that have achieved the best results - the Lao People's Democratic Republic, Timor Leste and Liberia - those are the top three - I think in all of those three aid has been a very important contributor," said Unicef's UK director, David Bull.

Efforts to target infectious diseases such as measles have cut related deaths globally from 500,000 in 2000 to 100,000 in 2011,

Fragile situations

Last year, half of global under-fives deaths occurred in just five countries, Unicef said - India, Nigeria, the Democratic Republic of Congo, Pakistan and China.

In some, mainly sub-Saharan countries, the total number of deaths of children younger than five increased in 2001.

The Democratic Republic of Congo, Chad, Somalia, Mali, Cameroon and Burkina Faso saw annual deaths of children under five rise by 10,000 or more in 2011 as compared with 1990.

Nearly all of the roughly 500,000 malaria deaths in under-fives occurred in sub-Saharan African states last year, the agency said.

Unicef said that conflict was a key contributing factor in child death: eight of the 10 countries with the highest rates of under-five mortality in conflict or fragile situations.

Across the planet, the five leading causes of deaths among children under five include pneumonia (18%); pre-term birth complications (14%); diarrhoea (11%); birth-related complications (9%) and malaria (7%).

Unicef explained that nearly half - around 40% - of deaths among children under five occur during the first 28 days of life. In 2011 alone, these accounted for about three million deaths worldwide.

Undernutrition, meanwhile, accounts for more than a third of such deaths.