South Korea's government said on Thursday it plans to ban cryptocurrency trading, sending bitcoin prices plummeting and throwing the virtual coin market into turmoil as the nation's police and tax authorities raided local exchanges on alleged tax evasion. Reuters reports: The clampdown in South Korea, a crucial source of global demand for cryptocurrency, came as policymakers around the world struggled to regulate an asset whose value has skyrocketed over the last year. Justice minister Park Sang-ki said the government was preparing a bill to ban trading of the virtual currency on domestic exchanges. Once a bill is drafted, legislation for an outright ban of virtual coin trading will require a majority vote of the total 297 members of the National Assembly, a process that could take months or even years. The local price of bitcoin plunged as much as 21 percent in midday trade to 18.3 million won (12,730.35 pounds) after the minister's comments. It still trades at around a 30 percent premium compared to other countries.