South Korean media quoted military officials as saying that North Korea had launched a ballistic missile.
According to the Jonheff news agency, the missile flew east.
It is not clear how far it was drawn or whether it was over Japan as early as earlier this year.
According to a statement issued by the South Korean Armed Forces, the missile has been released from Pyonggong, Pyeongan Province, North Korea.
North Korea has tested a number of missiles this year as nuclear warheads rise.
North Korea last September tested a last-minute ballistic missile just a few days after its sixth nuclear test.
South Korean military officials have been analyzing South Korean and US officials on this latest missile.
At the same time, the South Korean military said that it responded with its own missile response.
North Korea believed that long range missiles could be reached in the US mainland.
Although officials from Pyongyang said that they could launch a long-range missile last July in the world, the US military saw it as an intermediate-range missile.
Reports that North Korea had a small nuclear bomb that could carry a long-range missile to the last nuclear test has further exacerbated the warm tension with the United States. The United States imposed new sanctions against North Korea last week for North Korea's nuclear program. It was targeted at Chinese companies operating in the North Korean navy and China.