The two-day visit at the invitation of Afghan President Hamid Karzai was to be Singh's second since 2005. It comes in the wake of the May 2 killing of Osama bin Laden by U.S. forces in neighboring Pakistan, with whom India's relations remain strained since the Nov. 26, 2008, Mumbai terror carnage. Karzai last visited India in February.
In a statement before leaving, Singh said since his 2005 visit India-Afghan cooperation "has expanded significantly," including India's development assistance commitment of about $ 1.5 billion.
"India and Afghanistan enjoy a deep and abiding relationship that goes back in time and history. We are people of the same region. We cannot remain unaffected by developments in Afghanistan," Singh said.
"I look forward to wide ranging discussions with President Hamid Karzai and the Afghan leadership on ways to advance our partnership to a new level in the coming years," he said.
India's ties with Kabul are a source of concern for Pakistan as it seeks to increase its influence in Afghanistan.
"If our region is to prosper and move ahead, Afghanistan must succeed in rebuilding itself. Its people have suffered far too long. India's commitment to assisting the people of Afghanistan is enduring and has weathered many storms," Singh said in his statement.
The Times of India reported India wants to do more in the security sector, to train Afghan forces so they can take over when international troops leave the country.