North Korea has fired an unspecified ballistic missile toward its east coast, South Korea’s joint chiefs of staff said on Thursday morning, following joint South Korean and US missile drills and the return of a US aircraft carrier to the region in response to the North’s recent missile tests. Japan’s coast guard said North Korea may also have fired a second missile. The missile launch was the sixth in 12 days and the first since North Korea fired an intermediate-range missile over Japan on Tuesday. Foreign experts said the missile fired on Tuesday was capable of reaching the US Pacific territory of Guam and beyond. After Tuesday’s launch, the US, Britain, France, Albania, Norway and Ireland called for an emergency meeting of the UN security council. Hours earlier, North Korea condemned the US for repositioning an aircraft carrier in the waters off the Korean peninsula. The move posed a “serious threat” to the stability in the region, it said in a statement released by the reclusive nation’s foreign ministry. North Korea carried out a record number of missile tests this year amid long-stalled diplomacy with the US. Observers say North Korea aims to expand its nuclear arsenal to boost its leverage in future negotiations with the US.