RIYADH, Saudi Arabia — Saudi Arabia will test what it claims is the world’s largest clock in the holy city of Mecca during the Muslim fasting month of Ramadan, the official news agency reported Tuesday.

The four-faced clock tower sits atop a massive skyscraper that when completed will be around 1,970 feet tall, the second tallest in the world after Dubai’s Burj Khalifa.

The clock will dwarf London’s Big Ben, once the largest four-faced clock in the world, with dials more than five times greater in area. The 130-foot diameter Saudi clock dials are also bigger than the current world champion clock at the Cevahir Mall in Istanbul, which has a 118-foot face set in the transparent roof of the shopping complex.

The Saudi complex overlooks Mecca’s famed Grand Mosque, which Muslims worldwide face during their five daily prayers and is part of Saudi efforts to develop the city visited by millions of pilgrims every year.

A three-month test run for the clock will start during the first week of Ramadan – the monthlong period of prayer, reflection and sunrise-to-sunset fasting, the report said. This year, Ramadan begins today.

Only one of the clock’s four faces has so far been completed and is covered with 98 million pieces of glass mosaics.

Each face will be inscribed with “God is greatest” in Arabic and fitted with thousands of colored lights. The seven tower complex is being built by developer Saudi Binladen Group, the press agency reported.