KABUL (Reuters) - A roadside bomb killed an Afghan archaeologist near an ancient Buddhist excavation site, also home to the country’s largest copper reserve, raising concerns about increasing threats to government-backed projects, officials said on Sunday.

Security threats by insurgents have forced European and U.S. archaeologists to pull out of the Mes Aynak site in recent years, leaving Afghan experts to pursue the work on their own and try to prevent rampant illegal mining.

Saturday’s attack wounded four employees of the cultural ministry near the excavation site, 40 km (25 miles) south of the capital, home to the remains of 5,000-year-old temples, residential areas, markets and a fortress.

No group has claimed responsibility. Taliban militants, seeking to reimpose strict Islamic law after their 2001 ouster, blew up two ancient giant Buddha statues in Bamiyan province in March that year because they were deemed un-Islamic.

“We never thought such action would be taken against us, because we are neither military nor high-ranking government officials,” said archaeologist Mohammad Rabi Saber, a colleague of the victims. “But after this incident, a kind of fear has spread among the archaeology staff members.”

In 2008, a Chinese company, Metallurgical Corporation of China, was awarded a contract to recover copper from Mes Aynak but a series of protests to protect the Buddhist site stalled the project.

Afghan and international archaeologists began uncovering thousands of statues, manuscripts, coins and monuments at Mes Aynak in 2009. The government has said that all antiques from Mes Aynak will be excavated before mining begins.

The archaeologist who was killed, Abdul Wahab Ferozi, oversaw the repairs of more than 3,000 antiques from Mes Aynak that were handed to the National Museum in Kabul.

Police said Ferozi was on his way to the site when a remote-controlled bomb exploded near his car.

“We are trying the identify who planted the bomb. No insurgent group has claimed responsibility so far,” said Hashmat Stanakzai, spokesman for Kabul police.

At least 183 Afghan civilians were killed and 337 wounded in clashes and attacks nationwide in May, the Civilian Protection Advocacy Group, an independent monitor group, reported on Saturday.

Many local and international companies are reevaluating their hiring strategy because of the rising violence.