SEOUL - U.S. Defense Secretary Mark Esper asked South Korea to send troops to join a U.S.-led maritime force in the Strait of Hormuz off the coast of Iran, Yonhap news agency said on Friday.Esper made the request during a meeting with Defence Minister Jeong Kyeong-doo in South Korea, it added.Jeong told Esper Seoul was considering various options, since South Korean people and vessels are also using the strait.A South Korean defense ministry official did not have immediate comment.