Washington, Jul 25 (IANS): US President Barack Obama has mourned the death of his Ghanian counterpart John Evans Atta Mills at the age of 68, praising his role in the west African nation's development.

Mills had undergone a nine-day medical check-up in the US last month but died Tuesday, Xinhua reported.

"It was with great regret that I learned of the passing of President John Evans Atta Mills of Ghana," Obama said in a statement Tuesday, recalling his trip to the west African nation in 2009 and his hosting of Mills at the White House early this year.

"President Mills tirelessly worked to improve the lives of the Ghanaian people. He helped promote economic growth in Ghana in the midst of challenging global circumstances and strengthened Ghana's strong tradition of democracy."

"Under his leadership, the United States and Ghana deepened our partnership in the promotion of good governance and economic development," the US president said.

Meanwhile, Ghana's Vice President John Dramani Mahama was sworn in as new president hours after Mills' death.