North Korea fired several short-range missiles into the sea on Thursday, hours after the United Nations Security Council voted to impose new sanctions against Pyongyang.
The launch reinforce tensions on the Korean peninsula, which increased from a North Korean nuclear test in January and launch long-range rocket in February, and put the South Korean military on alert.
The Defense Ministry said South Korea is trying to determine whether the projectiles launched at 10:00 local time (0100 GMT) from the east coast of North Korea, were short-range missiles or artillery fire.
Park has been tough in its response to recent actions by North Korea on Thursday welcomed the initiative of the Security Council of the UN and repeated his call for Pyongyang to change its behavior.
"We will cooperate with the world to make the regime of North Korea to abandon its reckless nuclear development and to end the tyranny that oppresses freedom and human rights of our brothers in the North," Park said in a meeting Christian prayer on Thursday.
Also Thursday, South Korea passed a law establishing a security anti-espionage unit that was approved by Parliament on Wednesday, and another law aimed at improving human rights in North Korea.
Last month, Seoul suspended the activity in an industrial park that operates in conjunction with North Korea, cutting off the last route for normal communication was left of the two rivals.
North Korea faces new tough sanctions for its nuclear weapons program after the resolution adopted on Wednesday by the Security Council of the UN, a measure drafted by the US and backed by China, the main ally of North Korea.