It said the letter, reportedly written by the vice director of the Pentagon's Joint Staff, noted that such a conflict could prompt Pyongyang to deploy biological and chemical weapons.
The letter was sent from the US Defence Department regarding the prospects of war on the Korean peninsula in response form a request from 2 members of the US Congress seeking details regarding "expected casualty assessments in a conflict with North Korea" for US and allied forces in Japan, South Korea and Guam as well as civilians.
Trump's trip to South Korea is the first state visit by a US president in 25 years, with the USA president expected to be welcomed with a 21-gun salute on arrival, while the two leaders are scheduled to take a stroll around the Blue House and later attend a concert consisting of a fusion of classical music and traditional Korean music, and K-pop.
While the joint military drills between the US and South Korea that both sides say are defensive in nature they enrage South Korea's neighbor to the north - Pyongyang views them as practice for an eventual invasion.
Kim, who has also made clear he has little interest in negotiations, at least until North Korea develops a nuclear-tipped missile capable of hitting the United States, has called Trump a "mentally deranged US dotard".
North Korea's last nuclear and missile tests both occurred in September.
But Kang warned that "we need to be very careful about military options", adding that they "are there to give strength to diplomacy".
Iran To Reopen Border With Iraq's Kurdistan Region
The president's Kurdistan Regional Government said it had ordered the local police forces, known as Asayish, to stop the attacks. Opposition lawmakers who had been barricaded inside managed to leave later, according to their parties.
Trump kicked off a 12-day Asian trip and is looking to present a united front with Japan against North Korea through meetings with Prime Minister Shinzo Abe amid heightened tensions over Pyongyang's nuclear and missile tests.
Addressing the US military personnel stationed at the Japanese air base, Trump warned "no one, no dictator, no regime. should underestimate American resolve".
Trump will visit China from Wednesday to Friday.
Trump wants South Korea to pay more for the US military presence on its soil, which is chiefly aimed at deterring potential aggression from North Korea. He said of the 300,000 people who could potentially die in the initial days, more than 100,000 could be Americans.
Givens, who spent four years stationed in Korea, added that the figures did not take into account potential use of nuclear weapons by Pyongyang. With North Korea's defeat - but at what cost?,' Givens said.
North Korea has said in public statements that it wants an official end to the Korean War.
Beijing has pleaded with both the U.S. and Pyongyang to 'realize that resorting to military force will never be a viable way to resolve the peninsula issue and their own concerns, adding that 'War on the peninsula will have no victor'.