International donors pledged $16 billion in development aid for Afghanistan infrastructures by next 4 years on Sunday. 

They stressed the aid will be closely monitored to assure it is not squandered through corruption or mismanagement. The amount is in line with the $4 billion a year that Afghan President Hamid Karzai requested at Sunday’s conference.

The conference is attended by representatives of about 70 countries and senior world officials, including U.N. Secretary-General Ban Ki-moon and U.S. Secretary of State Hillary Clinton.

In his opening remarks, Mr. Karzai acknowledged that endemic corruption in Afghanistan has undermined previous aid efforts, and he promised to do more to bring that under control.

“I am encouraged that the member states are willing to mobilize $16 billion,” said U.N. Secretary-General Ban Ki-moon. “Afghanistan has made important progress, but the gains are fragile.”

Japan, the second-largest donor, says it will provide up to $3 billion through 2016, and Germany has announced it will keep its contribution to rebuilding and development at its current level of $536 million a year, at least until 2016.

The Afghan central bank has estimated that at least $6-billion a year in new investment from foreign donors will be needed to foster economic growth over the next decade.