Sharif, who became his country's prime minister for the third time after elections in May, is visiting the United States at a time when both sides are trying to further improve their rocky relations as Pakistan remains an ally in the fight against terrorism.
Sharif was scheduled to meet with Obama on Wednesday.
"The prime minister's official visit comes as we are strengthening U.S.-Pakistan relations," White House press secretary Jay Carney said at his media briefing.
"We want to advance our shared interest of a stable, secure, and prosperous Pakistan that is contributing to regional and international security and prosperity," Carney said. "We want to find ways for our countries to cooperate, even as we have differences on some issues, and we want to make sure that the trajectory of this relationship is a positive one."
He described U.S.-Pakistan relationship as "a very important" one that obviously has "got a lot of complexity to it, but it's enormously valuable when it comes to U.S. national security and to the safety and security of the American people."
Earlier, prior to his meeting with Sharif, U.S. Secretary of State John Kerry said the relationship with Pakistan "could not be more important.''
Ahead of Sharif's visit, Washington decided to release more than $1.6 billion in military and economic aid to Pakistan. The aid was suspended after relations hit a low following the U.S. raid in 2011 in which al-Qaida leader Osama bin Laden was killed in his compound in Pakistan. Relations also have been deeply affected by other issues such as the U.S. drone strikes against militants who use their Pakistani sanctuaries to launch attacks on U.S. and NATO troops in neighboring Afghanistan.
One area where Sharif reportedly failed to win U.S. support was over Pakistan's decades-long dispute with neighboring India over Kashmir.
Before reaching Washington, Sharif had been quoted as saying U.S. intervention would resolve the Kashmir issue between India and Pakistan.
The United States, as part of its effort to maintain close relations with India, has refused to get involved in the Kashmir dispute, maintaining it is a bilateral issue which India and Pakistan must settle on their own.
Pakistan's Dawn newspaper reported U.S. officials refused to endorse Sharif's call for internationalizing the Kashmir dispute and instead urged him to stay engaged with India for resolving it. One U.S. official was quoted as saying: "On Kashmir, our policy has not changed an iota."
The report also said that while reviewing Sharif's meeting with Obama, senior U.S. administration officials said the United States and Pakistan would continue to discuss the drone strikes in Pakistan's tribal areas but only as part of a larger security issue.
Officials also said the Obama-Sharif meeting would focus on bilateral relationship, including energy, economy and extremism, Dawn reported. Pakistan's relations with India and Afghanistan would also figure in the talks.
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