Japan has informed the UN of its intention to increase assistance to Afghanistan to $5 billion over the next five years, the UN said.
Japan decided to add $2 billion to the current $3 billion it had allocated for assistance to war-torn Afghanistan.
UN Secretary General Ban Ki-moon welcomed Japan's generosity, calling it a "very positive development". He urged other governments to follow suit.
"The secretary general appreciates Japan's generous and continued contributions to the efforts and commitment of the international community to promote reconstruction and stability in Afghanistan," a UN statement said Wednesday.
Japan is among the largest donors in foreign assistance to Pakistan and Afghanistan. Welcoming the announcement, the US said this commitment reflected "Japan's crucial leadership in the region and around the globe".
As US President Barack Obama prepares to travel to Japan on Thursday, "he looks forward to renewing our strong alliance with Japan, and discussing our continued partnership on Afghanistan, Pakistan, and critical bilateral issues", a White House statement said.