North Korea has fired six short-range projectiles into the sea, Seoul officials said, just hours after the UN Security Council approved the toughest sanctions on Pyongyang in two decades for its recent nuclear test and long-range rocket launch.
Thursday's launches on Thursday morning also come shortly after Seoul's parliament passed its first legislation on human rights in North Korea.
Defence spokesman Moon Sang Gyun said the projectiles were fired from the eastern coastal town of Wonsan, adding that authorities were trying to determine what exactly North Korea fired.
The projectiles could be missiles, artillery or rockets, according to the defence ministry.
North Korea routinely test-fires missiles and rockets, but it often conducts more weapons launches when angered at international condemnation.
Pyongyang conducted its fourth nuclear test in January, making the widely disputed claim that it successfully detonated a hydrogen bomb.
Last month, it put a satellite into orbit with a long-range rocket that the United Nations and others see as a cover for a test of banned ballistic missile technology.
The new UN sanctions include mandatory inspections of cargo leaving and entering North Korea by land, sea or air; a ban on all sales or transfers of small arms and light weapons to Pyongyang; and expulsion of diplomats from the North who engage in "illicit activities".
The official North Korean news agency KCNA said on Monday the proposed sanctions were "a wanton infringement on [North Korea's] sovereignty and grave challenge to it".
The UN Security Council resolution was passed after being thoroughly negotiated by Washington and Beijing, the closest ally of the Pyongyang government.
US Ambassador to the UN, Samantha Power, said the new sanctions against North Korea go further than any UN sanctions regime in two decades, and are aimed at cutting off funds for its nuclear and other banned weapons programmes.
"Our collective security demands that we stop North Korea from continuing along this destructive and destabilising course," Power said.
"Yet, we've got to be honest, that while previous multilateral efforts, including the four previous sanctions resolutions adopted by this Council, have undoubtedly made it more difficult for North Korea to advance its weapons programmes, the regime continues to plough ahead as it demonstrated the last two months.
"That is why the resolution we have just adopted is so much tougher than any prior North Korea resolution."
Power said the new sanctions on North Korea go further than any UN sanctions regime in two decades [EPA]
Under the sanctions, North Korean trade representatives in Syria, Iran and Vietnam are among 16 individuals added to a UN blacklist - along with 12 North Korean entities.
North Korea has been under UN sanctions since 2006 because of its four nuclear tests and multiple rocket launches.
Al Jazeera's James Bays, reporting from the UN headquarters in New York, said the new sanctions resolution was trying to deal with some of the loopholes North Korea has used in the past.
"They've changed some of the names of the front companies; they've named new individuals; they are trying to find every way to crack down on North Korea," Bays said.
"All experts agree that these are the toughest, most detailed sanctions to date."
Bays added that the resolution included "some elements that are supposed to target the leadership of North Korea. On the last page of the resolution, there are sanctions against exporting luxury goods into the country," he said.
The list on luxury goods include luxury watches, aquatic recreational vehicles, snowmobiles worth more than $2,000, lead crystal items and recreational sports equipment.
In Seoul, South Korea's National Assembly passed the human rights bill shortly before the UN sanctions were unanimously approved. It will become law after it is signed by President Park Geun-hye.
North Korea has warned that enactment of the law would result in "miserable ruin." It views any criticism of its rights situation as part of a US-led plot to overthrow its government, a reason why it says it needs nuclear weapons.

The bill would establish a centre in South Korea's unification ministry tasked with collecting, archiving and publishing information about human rights in North Korea.
It is required to transfer that information to the justice ministry, a step parliamentary officials say would provide legal grounds to punish rights violators in North Korea when the two Koreas eventually reunify.
Source: Al Jazeera and agencies