North Korea has test-fired two ground-to-ship missiles from its east coast, the South Korean Yonhap news agency has reported.

One was fired at 5.20pm (0820GMT) and the other at 6.00pm (0900GMT), a South Korean defence ministry spokesman said.

Leonid Petrov, a North Korean specialist from the Australian National University, told Al Jazeera: "We had been expecting the test fire of a medium-range missile in early July.

"These were short range missiles, which are a defensive measure, and may have been done ... to impress [North Korean leader] Kim Jong-il who was visiting."

Growing tensions

South Korea's joint chiefs of staff could not immediately confirm the report on Thursday.

North Korea had earlier issued a no-sail zone in waters off its east coast through July 10.

The move comes a week after the United States extended economic sanctions against North Korea for another year as tensions grew over the communist state's nuclear activities.