North Koreans have gathered in Pyongyang for a mass rally to celebrate Wednesday's long-range rocket launch.

State television showed huge crowds cheering to mark the launch, which has been condemned by many nations as a banned test of missile technology.

South Korea, meanwhile, says it has retrieved debris from the rocket and will study it to assess its technology.

The first stage of the rocket fell west of the Korean peninsula. South Korea's navy located it shortly afterwards.

It was North Korea's first successful use of a three-stage rocket to put a satellite into orbit. North Korea said on Friday that more launches would go ahead.

The UN Security Council has condemned the launch, calling it a missile test that violated two UN resolutions banning Pyongyang from such activities passed after its nuclear tests in 2006 and 2009.

The US, South Korea and Japan - who believe North Korea is working to develop long-range missiles capable of carrying nuclear warheads - want action such as the strengthening of sanctions.

But China - North Korea's main ally - says any UN response should be "conducive to peace" and avoid escalating tensions.

'Unshakeable stand'

In Pyongyang, state television showed ranks of North Koreas listening to congratulatory speeches about the launch.

The rocket was launched from the North Korean coast early on Wednesday. South Korea says a fuel container was found where the first stage of the rocket separated.

"The Navy's Deep Submergence Rescue Vehicle retrieved the debris of the rocket's first stage at 00:26 and was delivering it to the Second Command Fleet in Pyeongtaek," Yonhap news agency quoted a defence ministry official as saying.

It would be "useful material for analysis", another ministry spokesman said.

On Friday a statement from North Korea's KCNA news agency said leader Kim Jong-un had called for more such launches.

North Korea "showed at home and abroad the unshakable stand... to exercise the country's legitimate right to use space for peaceful purposes", the KCNA statement quoted him as saying.

The US, meanwhile, said it was holding talks with key players on how to respond to the launch.

"We are working with both our six party partners and with our UN Security Council partners - China is in both of those categories - on a clear and credible response to what the North Koreans have done," State Department spokeswoman Victoria Nuland said.