North Korea on Thursday reiterated its pledge to bolster its nuclear deterrence both in quality and quantity against what it called US hostile acts, the country's state-run media said. 
North Korea defended its latest test of intermediate range missiles, saying that it is natural for the country to take steps to boost nuclear deterrence to counter Washington's constant threats, according to the Korean Central News Agency (KCNA). 
North Korea "will continue taking a series of steps for bolstering up the nuclear deterrent for self-defense both in quality and quantity to cope with the ever-escalating US hostile acts against the former," a spokesman at the foreign ministry was quoted as saying by the KCNA. 
Pyongyang claims that the US constantly poses a nuclear threat to the North, saying that Washington brought strategic assets including nuclear-powered submarine Mississippi and B-52H strategic bombers to the Korean Peninsula.

Source ; QNA