US President Barack Obama congratulated Pakistan's Nawaz Sharif in a phone call Tuesday on his party's success in parliamentary elections, the White House said. Obama and Sharif agreed to work together to strengthen ties between their countries and "advance our shared interest of a stable, secure, and prosperous Pakistan and region. " Obama also praised Sharif "for his role in the historic transfer of power between civilian governments, a significant milestone in Pakistan's democracy" and the high voter turnout despite threats of intimidation by extremists.