UNITED NATIONS — The U.N. imposed new sanctions Thursday against five North Korean officials, four companies and a state agency, and banned imports of two weapons-making materials, in a rare unified push by the world's powers to thwart Pyongyang's nuclear ambitions.

The sanctions, which take immediate effect and are to be carried out by all of the U.N.'s 192 member nations, include travel bans and a freeze on the financial assets against the officials, companies and state agency. Nations also were instructed to refrain from supplying North Korea with certain types of graphite and para-aramid fiber — two of the materials used in ballistic missile parts.

"It is of course significant that we have also put individuals on the list, as this is the first time. This shows that the sanctions are going on a higher level at this moment," said Fazli Corman, Turkey's deputy U.N. ambassador, who chairs the panel.

The newest sanctions were approved against:

_The General Bureau of Atomic Energy in Pyongyang, the chief agency directing the North's nuclear program. That includes the Yongbyon Nuclear Research Center and its plutonium production research reactor, as well as its fuel fabrication and reprocessing facilities.

_Three Pyongyang-based companies — Namchongang Trading Corp., Korea Hyoksin Trading Corp., and Korean Tangun Trading Corp. — and one Iranian-based company, Hong Kong Electronics.

_Yun Ho-Jin, director of Namchongang Trading Corp.; Ri Je-Son, director of the General Bureau of Atomic Energy; Hwang Sok-Hwa, chief of the bureau's scientific guidance; Ri Hong-Sop, former director of Yongbyon Nuclear Research Center; and Han Yu-Ro, director of Korea Ryongaksan General Trading Corp.

_Two types of goods used in ballistic missile parts by North Korea — a graphite designed or specified for use in electrical discharge machining; and a para-aramid fiber, filament and tape, which is a Kevlar-like material.

U.S. Ambassador Susan Rice said the United States was pleased with the list, which required unanimous approval among the 15 nations that make up a sanctions panel of the U.N.'s powerhouse Security Council. China, North Korea's biggest ally and trading partner, went along with most of the U.S. recommendations.

The U.S. has launched what it calls a major effort to ensure that U.N. Security Council Resolution 1874, which along with a previous resolution in 2006 serves to authorize the latest sanctions, is implemented effectively.

"These new designations — five individuals, five entities and two goods — strengthen the sanctions regime against North Korea and will serve to constrain North Korea from engaging in transactions or activities that could fund its WMD or proliferation activities," Rice said.

The sanctions panel, which said it plans to add still more names and entities, has been focused on three areas: sensitive dual-use goods, ballistic missile-related items and nuclear-related items.

A U.S. expert on North Korean sanctions said the latest measures — putting the U.N. seal of approval on measures the U.S. already has prepared to undertake — are "a modest first step" that might scare off some of North Korea's weapons-buying customers.

"We're now into a game of Whack-A-Mole," said Marcus Noland, an economist at Washington-based Peterson Institute for International Economics, referring to the game in which moles keeping popping up from their holes randomly.

"What's going to happen is that the North Koreans are going to try to reconstitute their entities and form new shell companies, new front companies, to continue these activities," he said. "If there's really going to be comprehensive efforts on this, they're going to have to go after the financial intermediaries, some of which are in China, and after the customers."

North Korea has not indicated how it might react to the sanctions panel's latest decisions.

But on June 13, North Korea's Foreign Ministry threatened to take "countermeasures" including accelerating plutonium reprocessing and starting up uranium enrichment, which would give the regime a second way to make atomic bombs.

North Korea warned that any attempted blockade of its ships would be considered "an act of war" that would draw "a decisive military response." It also has threatened a "thousand-fold" military retaliation against the U.S. and its allies if provoked.

Security Council Resolution 1874, approved on June 12, responded to the North's underground nuclear test blast on May 25. It called for clamping down on alleged trading of banned arms and weapons-related material and stepped-up inspections of suspect shipments by sea and air.

Since then, the council also has condemned and expressed "grave concern" over North Korea's recent firing of seven ballistic missiles on U.S. Independence Day. The missile launches off the nation's east coast defied three previous council resolutions and further aggravated tensions already high after North Korea's May 25 test blast.

Japan, which lives in constant fear of a nuclear-armed North Korea, asked all Southeast Asian nations, except junta-ruled Myanmar to enforce the U.N.'s North Korea resolutions.

A North Korean ship, the first to be monitored under the June 12 resolution, turned back before reaching port, possibly in Myanmar, with its suspected illicit cargo of weapons.