North Korea fired two short-range missiles into waters off its east coast Monday, Yonhap News Agency reported.

The missiles were launched from the Gitdaeryeong area and Wonsan, both on the east coast, beginning at 6:19 a.m., Yonhap quoted an unidentified South Korean official as saying.

"It is believed the missiles flew as far as 500 kilometers," the official said.

Last Thursday, North Korea fired four projectiles believed to be short-range missiles into the Sea of Japan, according to South Korea's Defense Ministry.

The projectiles apparently flew more than 200 km, an official of the ministry said.

The missile firings came after South Korea and the United States began their annual joint military drills in the South last Monday.