North Korea on Friday threatened "physical counter-measures" against rival South Korea -- the latest in a series of bellicose warnings sparked by a tightening of U.N. sanctions against Pyongyang.

"If the South Korean puppet regime of traitors directly participates in the so-called U.N. 'sanctions,' strong physical countermeasures would be taken," the North's Committee for Peaceful Reunification of Fatherland said.

The United Nations said Thursday that the international community must put "pressure" on North Korea to stop it carrying out a nuclear weapons test.

"The international community has to bring pressure to bear on the North Koreans," a spokesman for U.N. leader Ban Ki-moon told reporters.

The U.S. Treasury on Thursday imposed sanctions on two Beijing-based North Korean bankers for their role in exporting Pyongyang's weapons technology and equipment, including to Iran.

Also named for sanctions was a Hong Kong-based trading company which the Treasury said facilitates weapons-related shipments on behalf of Pyongyang's "premier arms dealer," the Mining Development Trading Corporation known as KOMID, the Treasury said.

North Korea's sole major ally China urged "all relevant parties" to show restraint Thursday after Pyongyang said it planned to carry out a third nuclear test and more rocket launches aimed at the U.S.

"All relevant parties should refrain from action that might escalate the situation in the region," foreign ministry spokesman Hong Lei told reporters in Beijing.

North Korea said Thursday it planned to carry out a third nuclear test and more rocket launches aimed at its "arch-enemy" the United States in response to tightened U.N. sanctions, but offered no timeframe.

"We do not hide that the various satellites and long-range rockets we will continue to launch, as well as the high-level nuclear test we will proceed with, are aimed at our arch-enemy the United States," the National Defense Commission said.

Japan is to launch a new spy satellite on Sunday to strengthen its monitoring capabilities amid concern that North Korea may carry out more missile and nuclear tests.

A rocket carrying a radar-equipped satellite is scheduled to blast off from a space center at Tanegashima in the southwest, the Japan Aerospace Exploration Agency has announced.

North Korea is loosening some restrictions on foreign cellphones by allowing visitors to bring their own phones into the country. However, security regulations still prohibit mobile phone calls between foreigners and locals.

For years, North Korea required visitors to relinquish foreign cellphones at the border until their departure, leaving many tourists without an easy way to communicate with the outside world.

The United States and China have made a deal under which the U.N. Security Council will expand existing sanctions against North Korea for staging a ballistic missile test, envoys said Friday.

The deal was struck after weeks of intense negotiations following the December 12 launch. The talks have involved U.S. Secretary of State Hillary Clinton and her Chinese counterpart Yang Jiechi, according to envoys.

South Korea plans to deploy Israeli-made precision guided missiles near its tense sea border with North Korea next month, including an island shelled by the North in 2010, a report said Friday.

The South will deploy 50 to 60 Spike anti-tank missiles to two border islands on the Yellow Sea to guard against potential attacks from the North, the Chosun Ilbo daily cited a Seoul military official as saying.

Japan's top nuclear envoy on Thursday urged the U.N. Security Council to act "sooner rather than later" in punishing North Korea for its long-range rocket launch in December.

"We agreed that the Security Council, on behalf of the entire international community, must take appropriate action," Shinsuke Sugiyama told reporters after talks in Seoul with his South Korean counterpart, Lim Sung-Nam.