The Obama administration will ask Congress to sustain U.S. assistance for Afghanistan near the average amount it has been over the last decade through 2017 as part of the international effort to stabilize the country even as most international forces pull out over the next two years.

U.S. Secretary of State Hillary Rodham Clinton made the pledge Sunday as some 70 countries gathered in Tokyo to announce a four-year civilian assistance plan. Altogether they are promising to give $16 billion to Afghanistan through 2015.

The funds would help Afghanistan build its economy and make necessary reforms, Clinton said.

"We have to make the security gains and the transition irreversible," Clinton told officials, including Afghan President Hamid Karzai.

She said Afghan security "cannot only be measured by the absence of war."

"It has to be measured by whether people have jobs and economic opportunity; whether they believe the government is meeting their needs," Clinton said.

Clinton said Afghanistan has made substantial progress over the last decade, but needs effective collaboration between its government, private sector, neighbors and international donors "so that this decade of transformation can produce results."

Annual U.S. civilian assistance since 2001 has ranged from $1 billion to this year's high of $2.3 billion.

Clinton said the aid request to Congress through 2017 would be to maintain funding at or near the average level, without specifying further.