https://www.reuters.com/article/us-southkorea-japan-labourers-trade/south-korean-trade-official-says-japans-export-curbs-violate-wto-rules-idUSKCN1TW1A4 >Japan's decision to tighten curbs on tech material exports to South Korea violates World Trade Organization rules and Seoul would respond firmly, a senior official at South Korea's trade ministry said on Monday.