Ban arrived in Seoul earlier in the day for a 53-nation nuclear security summit on Monday and Tuesday, which takes place under the shadow of Pyongyang's plan to launch a rocket to purportedly put a satellite into orbit.

The United States, Australia and other nations see the move as a pretext for a long-range missile test banned by the UN.

"President Lee and Secretary-General Ban shared an understanding that North Korea's announced plan to launch a rocket is in breach of a UN Security Council resolutions," Lee's office said in a press statement.

"They expressed concerns over the launch which they agreed would be a grave provocative act against the international community." the office said.

South Korea's Yonhap news agency said both sides agreed to work closely together to deal with any threats arising from the proposed rocket launch.

In Kuala Lumpur, Ban Ki-moon said on Thursday that he would raise North Korea's planned rocket launch at the Seoul summit next week, expressing "deep concern" over the issue.

Pyongyang has said any South Korean attempt to address the North's nuclear programme at the March 26-27 summit would be seen as a declaration of war.

But the programme and the rocket launch were expected to be hot topics on the sidelines of the meeting, which will see US President Barack Obama and other world leaders meet to discuss nuclear security issues.

A UN Security Council resolution passed after the North staged missile and nuclear tests in 2009 bans a ballistic missile launch for any purpose.

Ban said in Kuala Lumpur that it could also undermine recent positive signs on long-running diplomatic efforts to end North Korea's nuclear programme.

N. Korea launch to bring strong response: US official
Seoul (AFP) March 23, 2012 - North Korea will face a "strong response" if it launches a long-range rocket next month despite international calls to desist, a special adviser to US President Barack Obama said Friday.

"If they go ahead anyway, we will want to work with our allies and partners for a strong response," Gary Samore, arms control coordinator at the National Security Council, told South Korea's Yonhap news agency in an interview.

The North's planned launch sometime between April 12 and 16 will be a key topic on the sidelines of a nuclear security summit in Seoul next week.

Obama has scheduled talks with Chinese President Hu Jintao, South Korean President Lee Myung-Bak and other leaders attending the two-day event starting Monday.

The North says it aims only to put a satellite into orbit for peaceful space research. The United States and its allies see the plan as a pretext for a long-range missile test, banned under UN Security Council resolutions.

"We have urged North Korea not to proceed with the announced satellite launch," Samore said.

"We will be working with other countries, when President Obama is here (in Seoul), to try to discourage North Korea from going ahead with the proposed satellite launch."

Asked about whether Pyongyang could be referred to the Security Council if it goes ahead, Samore told Yonhap: "Then, we will work with our friends to figure out what the most appropriate response will be."

"All parties should keep calm and exercise restraint and refrain from actions that would complicate the issue," foreign ministry spokesman Hong Lei told reporters.

The nuclear-armed North has announced it will launch a rocket in mid-April to put a satellite into orbit, a move that the United States, South Korea and other nations see as a pretext for a long-range missile test banned by the UN.

The move by North Korea's new leadership has set off alarm bells across the region, including in China -- Pyongyang's closest ally -- which last week expressed concern over the launch and urged restraint.

Hong said Beijing had made immediate contact with North Korea, Russia, Japan, the United States and other parties when it found out about the planned rocket launch.

"We stressed that peace and stability in the Korean peninsula and Northeast Asia is (in) the common interest of all parties and also their common responsibility," he said.

Japan's defence minister said Friday he had ordered officials to ready missile defence systems to shoot down the rocket if it threatens the country, just as world leaders prepared to meet in Seoul for a nuclear summit.

The North's atomic programme is expected to be the subject of discussion at the talks on Monday and Tuesday, which will be attended by US President Barack Obama, Chinese President Hu Jintao and the leaders of Japan and Russia.

US, Philippines monitoring planned rocket launch
Manila (AFP) March 24, 2012 - The Philippine and US militaries are coordinating to track the path of a planned North Korean rocket launch, parts of which are expected to land off the archipelago, an official said Saturday.

"The Philippine military is coordinating with its US counterpart in the monitoring of the planned launch," Foreign Department spokesman Raul Hernandez told AFP.

His announcement came a day after the USS Blue Ridge, the flagship of the US 7th Fleet in the Pacific, arrived in Manila for a four-day visit.

Hernandez did not divulge details of the joint monitoring, but the allies were expected to hold large-scale joint military exercises in the middle of April to enhance cooperation in case of external threats.

"We continue to strongly urge the DPRK (North Korea) not to proceed with its planned launch," Hernandez said.

"They should abide by the UN Security Council resolutions which explicitly demand that they do not conduct any launch using ballistic missile technology."

Manila's defence chief, Voltaire Gazmin, said Friday the government needed US help in tracking the rocket's path, with the poorly equipped Philippine military not having the capability to do so by itself.

Pyongyang announced last week it would launch the rocket to place a satellite in orbit between April 12 and 16, and insisted it was purely for space research.

But the United States and other nations see the launch as a disguised ballistic missile test, and say that it would breach a UN ban on North Korean missile launches.

A previous North Korean long-range rocket in 2009 flew over Japanese territory and the boosters landed safely in waters off Japan.

Kurt Campbell, the US assistant secretary of state for East Asian and Pacific Affairs, said the rocket launch would impact "in an area roughly between Australia, Indonesia and the Philippines," in a message to Australia's Foreign Minister Bob Carr, according to a report by the Sydney Morning Herald.