Seoul, March 23 : South Korea's Defence Minister Lee Jong-sup on Thursday said that North Korea fired four cruise missiles the previous day, though a detailed analysis is still underway to confirm the specifics. Seoul's Joint Chiefs of Staff has said it detected "multiple" missile launches from the North's eastern city of Hamhung on Wednesday morning, reports Yonhap News Agency. "We believe four (missiles were fired)," the Minister said during a session of the National Assembly's committee on national defence. "We have conducted the initial analysis, and the South and the US are examining it in a more detailed way." Commenting on whether the North has secured technologies to miniaturize a nuclear warhead and mount it on tactical weapons, the Lee said the country is seen as having achieved "considerable" progress. The North has been ratcheting up tensions through missile provocations, including a Hwasong-17 intercontinental ballistic missile launch last week, as the South and the US are conducting a major combined military exercise. It followed the launch of two short-range ballistic missiles on March 14 and of what it claimed to be two "strategic cruise missiles" from a submarine two days earlier. /IANS