KABUL, Afghanistan — U.S. Defense Secretary Chuck Hagel flew into Kabul on Saturday amid frustration in Washington over the Afghan president's refusal to sign an accord allowing NATO troops to stay in the country beyond next year.

US officials said no meeting was scheduled with President Hamid Karzai, but the president's spokesman said Karzai and Hagel were due to hold talks later Saturday — the latest sign of discord between the allies.

Washington and its allies have appealed to Karzai to sign the Bilateral Security Agreement (BSA), which lays out the rules for U.S. and NATO troops to operate in the country after 2014 on a mission focused on training and countering al-Qaida-linked extremists.

"Secretary Hagel does not plan to meet with President Karzai while in Afghanistan," a senior U.S. defense official told reporters.

"The United States has made its position on the BSA clear. And just two days ago, President Karzai repeated his position to senior U.S. officials that he is not yet ready to sign the BSA and provided no timeline or practical step for doing so."

But Karzai's spokesman Aimal Faizi told AFP that the Afghan president was expecting to hold talks with Hagel on Saturday — setting the stage for another diplomatic row after a long series of public disagreements.

"In our schedule for the president today we have a meeting with Secretary Hagel this evening with the president followed by a dinner with him," Faizi said, adding that Afghanistan was keen to discuss sticking points in the BSA talks.

"If there is any story around that the guest will be in Kabul but will not meet with the president that is false," Faizi said.