Iraqi soldiers arrested three smugglers who were trying to sell artefacts from the Sumerian era, the earliest known human civilisation that existed in southern Mesopotamia from about 8,000 years ago, Reuters reported. Undercover agents posed as buyers for the artefacts on Saturday, the army chief of Kirkuk province Major-General Abdul Ameer al-Zaidi told a news conference. The eight artefacts included a clay bust of what is believed to be a Sumerian king, a small jar and stamps from the royal Sumerian court. The smugglers had asked $160,000 for all eight. "We received intelligence tips about a group trying to sell precious antiques in a small town called al-Abbasi. We formed an undercover intelligence team to meet the smugglers and pretend to be interested in buying the eight pieces," Zaidi said. Iraq is struggling to recover numerous ancient treasures. Iraq's ancient sites are poorly guarded. Thieves often snatch pieces from Sumerian, Babylonian or Assyrian times. The Sumerian period is known for its clay tablets that bear one of the world's earliest systems of writing.