Media playback is unsupported on your device Media caption US ambassador to the UN, Susan Rice, said the sanctions on luxury goods would "bite hard" for North Korean officials

The UN Security Council has unanimously approved fresh sanctions against North Korea in response to Pyongyang's nuclear test last month.

The resolution is targeting North Korean diplomats, cash transfers and access to luxury goods.

It imposes asset freezes and travel bans on three individuals and two firms linked to North Korea's military.

Pyongyang earlier vowed to use its right to a pre-emptive nuclear attack against its "aggressors".

'Grave threat'

Analysis This is the fourth set of UN Security Council sanctions directed against North Korea following earlier nuclear tests and a long-range missile launch. Previous measures may have slowed the development of these systems but they have done little to change Pyongyang's behaviour. China backed the previous rounds of sanctions, too. Much will depend upon how far Beijing is actually prepared to implement new and existing sanctions. Some wonder if this vote, coming as a new Chinese leadership is establishing itself, may signify - at the very least - a signal of a desire for a more constructive relationship with Washington. Of course, the big question is how will North Korea respond. It has huffed and puffed in advance, even threatening a pre-emptive nuclear strike against the US. This is a highly charged moment on the Korean Peninsula and perhaps the greatest test yet for North Korea's young and inexperienced leader Kim Jong-un.

In a 15-0 vote, the council on Thursday backed Resolution 2094, imposing the fourth set of sanctions against the North.

Speaking after the vote, the US ambassador to the UN, Susan Rice, said the document "strongly condemns" Pyongyang's actions.

She said the sanctions would "further constrain" North Korea's ability to develop its nuclear programme.

And Ms Rice warned that the UN would "take further significant actions" if Pyongyang were to carry out another nuclear test.

"North Korea will achieve nothing by continuing threats and provocations," she stressed, urging the North to comply with the demands of the international community.

China's UN ambassador, Li Baodong, said that "the top priority now is to defuse the tensions" on the Korean peninsula.

Mr Li also said that the six-party talks on the North's controversial programme must resume.

South Korea's envoy to the UN, Kim Sook, described the North's nuclear tests as "grave threat to the peace" on the Korean peninsula and the wider region.

Mr Kim urged Pyongyang to respond to the concerns of the world community. "North Korea's future rests in its own hands," he said.

Russian ambassador Vitaly Churkin, who is the current president of the council, described the resolution as an "appropriate measure".

Resolution 2094 Strongly condemns North Korea's ongoing nuclear activities, including its uranium enrichment programme

Imposes new sanctions to block financial transactions and bulk cash transfers in support of illicit activity

Strengthens states' authority to inspect suspicious cargo

Requires states to deny port access to any North Korean vessel that refuses to be inspected

Calls on states to deny permission to any aircraft to take off, land in or overfly their territory if the aircraft is suspected of transporting prohibited items

Enables stronger enforcement of existing sanctions by UN member states

Sanctions new individuals and entities

UN Secretary General Ban Ki-moon said the measure "sent an unequivocal message to (North Korea) that the international community will not tolerate its pursuit of nuclear weapons."

Pyongyang has so far made no comments following Thursday's vote.

But earlier it accused the US of pushing to start a war.

"As long as the United States is willing to spark nuclear war, our forces will exercise their right to a pre-emptive nuclear strike," said North Korea's foreign ministry, in a statement carried by the KCNA news agency, without giving further details.

Earlier this week, Pyongyang also threatened to scrap the 60-year truce which ended the 1950-53 Korean War.

February's nuclear test, North Korea's third, followed its apparently successful launch in December of a three-stage rocket - a move condemned by the UN as a banned test of missile technology.

Pyongyang claims its nuclear test involved a smaller and more powerful device - prompting concerns it could be moving closer to creating a warhead small enough to arm a missile.