North Korea fired two short-range ballistic missiles off its east coast on Tuesday, South Korea's military said, the latest in a series of weapons tests as the South and the United States conduct their largest joint military drills in years.

The missiles were fired at around 7:40 a.m. (2240 GMT on Monday) from the South Hwanghae province, near the country's west coast, South Korea's Joint Chiefs of Staff (JCS) said.

The South Korean military was on high alert and maintaining full readiness posture under close coordination with the United States, the JCS added in a statement.

Japanese Prime Minister Fumio Kishida said Japan was collecting information on the missile, and that they have not confirmed any damage within the country related to the launch.

The launch comes two days after North Korea test-fired what it called two strategic cruise missiles from a submarine, and less than a week after North Korean leader Kim Jong Un ordered the military to intensify drills to deter and respond to a "real war" if necessary.

South Korean and American forces began 11 days of joint drills, dubbed "Freedom Shield 23," on Monday, which will be held on a scale not seen since 2017 to counter the North's growing threat.

North Korea has long bristled at the allies' drills as a rehearsal for invasion.

On Sunday, North Korean state media KCNA reported the country has decided to take "important practical" war deterrence measures, saying, "War provocations of the U.S. and South Korea are reaching the red-line."

North Korea has conducted a record number of missile tests and drills in the past year in what it says is an effort to boost its nuclear deterrent and make more weapons fully operational.