A total of 1,574 cultural relics have been discovered on a metro line construction site in northwest China's Xi'an City, of which 1,356 ancient tombs were dug up, Shaanxi News, a local news outlet, said on Thursday.

Archaeologists, construction workers and security guards were all on duty during the Spring Festival vacation to excavate the area and ensure smooth progress of the line 4 construction.

The 50-kilometer-long line is the only driverless loop line in the city. The relics and ancient tombs found on Changming Road where a train depot for the line is being built were from Sui and Tang Dynasties (581-907).

Apart from ancient tombs, around 140 pieces of ware have been dig up since February 5 and the archaeological work is continuing.

The frequent discoveries in the city are no longer a surprise. Almost the same time during the vacation, over 4,600 cultural relics were discovered at an expansion project of Xi'an's Xianyang International Airport.

"Archaeology is the main task now while metro construction comes second," a Weibo user with the handle of @zuiaichengbaola responded to the new underground discovery. Others commented that the archaeological department is the busiest administrative department.

An official with the city's Institute for the Preservation of Cultural Heritage has said that the heritage administration is involved in almost every metro construction site.

Back in 2009, hundreds of ancient tombs from Western Han (202 BC – 8 AD) to Ming Dynasty (1368 – 1644) were excavated at the construction sites of the city's line 2 while in March 2019, a relic site of Feiqiu, the ancient city of the Warring States period over 2,000 years ago, was found at the construction site of metro line 5 in Xi'an.

Relic sites are often discovered at other construction sites in the city, like a tomb of a princess from Tang Dynasty at the campus of Xi'an University of Architecture and Technology in 2017.

Statistics by the Shaanxi Administration of Cultural Heritage show that 179 archaeological projects were completed in 2020. A total of 3,956 ancient tombs were evacuated and 105, 800-square-meter ancient sites were discovered.