Pakistan's North West Frontier Province is celebrating Eid al-Fitr on Tuesday, a day before the rest of the country.
Pakistani women buy finery for Eid, watched by an armed guard
Religious scholars appointed by the province's government made the announcement after receiving over 100 reports of the new moon's sighting.
The appearance of the new moon at the end of the holy month of Ramadan is the
traditional signal to celebrate Eid.
Most Pakistanis will mark Eid on Wednesday or Thursday, depending on a decision by the federal religious body.
The federal body, which comprises delegates from all of Pakistan's provinces, fixes the date for all major religious celebrations, based on sightings of the moon.
It was meeting on Tuesday to decide when the rest of the country should observe the Eid festival.
The government of the North West Frontier Province (NWFP) usually holds a meeting of its religious scholars a day ahead of the federal body to decide if the new moon has been sighted at the end of Ramadan.
But this year's announcement to hold Eid a day early, based on witnesses' sightings of the moon, defies the authority of the
federal religious body.
Serious differences between the federal scholars and those sent by the six-party ruling coalition of the North West Frontier Province first emerged a month ago.
Two members from NWFP resigned in protest at committee chairman Munib Ur Rehman's alleged refusal to accept evidence about sightings of the new moon to mark the beginning of Ramadan.
However, the chief of the provincial committee, Qari Fayazur Rehman, has said Eid was being celebrated in NWFP with the consent of the federal government.
NWFP is governed by a coalition of Islamic parties who form one of the major opposition groups in Pakistan's capital, Islamabad.