ISLAMABAD - President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani on Wednesday congratulated Barack Obama and Senator Josph Biden, the newly elected President and Vice President, respectively, of the United States. President Zardari in his message expressed the hope that the relations between the two countries would further strengthen under the new American leadership. Zardari felicitated both Barack Obama and Senator Josph Biden on their election as US President and Vice President of the United States respectively. He expressed hope that Pak-US relations would further improve under the new leadership that received a popular mandate in Tuesday's election.    Yousuf Raza Gilani also congratulated the newly-elected US President Barack Obama. In his letter sent to the newly elected US President, the Prime Minister expressed hope that under his dynamic leadership, United States would continue to be a source of global peace and new ideas for humanity. "Your election marks a new chapter in the remarkable history of the United States. For long, the ideas of democracy, liberty and freedom espoused by the United States, have been source of inspiration for the millions around the world," Gilani said. The Prime Minister further said that Pakistan and the United States shared common interests and objectives. He mentioned his meeting with Barack Obama during visit to the United States in July where both had an opportunity to discuss issues pertaining to bilateral relationship. Gilani said, "I look forward to more opportunities to discuss ways to further strengthen Pakistan-US relations and promote peace and stability in our region and beyond." In a separate letter to Senator Joseph Biden, who will be the next Vice President of US, the Prime Minister conveyed his felicitations and said the elections marked a watershed in the history of the United States and the world. He said the new US administration would take charge at a time when the world was facing multiple challenges. "I hope we will work together to strengthen this strategic partnership between our two countries for enduring peace, security, stability and prosperity of our region and the world." The Prime Minister said, "The people of Pakistan consider you as a friend and look forward to your continued support and friendship as the Vice President of the United States of America."