U.S. Secretary of State John Kerry is in Iraq on an unannounced visit to urge Iraqi leaders to overcome sectarian differences that still threaten the country's stability following the 10-year anniversary of the American-led invasion that toppled dictator Saddam Hussein.

Secretary of State John Kerry (Chip Somodevilla/Getty Images)

Kerry flew into Baghdad on Saturday from Amman after accompanying President Barack Obama to Israel, the Palestinian Authority and Jordan. Officials traveling with him said he would press Iraqi Prime Minister Nouri al-Maliki and other senior officials on democratic reforms and urge them to stop overflights of Iranian aircraft carrying military personnel and equipment to support the Syrian government as it battles rebels.

The overflights have been a source of contention between the U.S. and Iraq and Kerry will tell the Iraqis that letting them continue will threaten Iraq's stability.

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