KABUL — US Secretary of State John Kerry extended talks Saturday with President Hamid Karzai on a bilateral security agreement with the United States, and while work remains to be done a deal could be struck by the end of the day, a presidential spokesman said. Aimal Faizi said some contentious issues remain to be finalized. Talks that began a year ago have been deadlocked over sovereignty issues and the safety of Afghan citizens at the hands of American and allied troops. “There is still some work to do on the document. Things are not yet finalized. It will be concluded hopefully this evening. Although it is not certain,” Faizi said. Kerry told US.Embassy staff after the meetings recessed that “we've had a terrific day.” “We're going back to the palace to enjoy dinner with the president and more importantly we're going to see if we can make a little more progress, which is what we have been trying to do all day long,” he added. “If this thing can come together, this will put the Taliban on their heels,” he added. “This will send a message to the community of nations that Afghanistan's future is being defined in a way that is achievable.” Kerry began negotiations with Karzai in the morning, the second day of talks after he arrived late Friday. The US wants a deal by the end of the month, while Karzai wants assurances over sovereignty that have deadlocked negotiations in the past year. Kerry is no stranger to marathon negotiations with Karzai. In October 2009, when Kerry was chairman of the Senate Foreign Relations Committee and on a visit to Afghanistan, he managed to broker an agreement for Karzai to accept a runoff presidential election after a UN election commission threw out one third of his votes claiming massive fraud. Kerry spent four days convincing Karzai to accept the runoff, which was later cancelled when the runner up quit the race. Karzai was re-elected for a second and final presidential term. — AP