SEOUL (Reuters) -South Korea has reached an agreement to lend the United States 500,000 rounds of 155mm artillery shells that could give Washington greater flexibility to supply Ukraine with ammunition, a South Korean newspaper reported on Wednesday. The DongA Ilbo newspaper cited unidentified government sources as saying South Korea decided to "lend" the ammunition instead of selling, to minimise the possibility of South Korean shells being used in the Ukraine conflict. South Korea's defence ministry said the allies have been exploring ways to support Ukraine but declined to confirm specific discussions.