Yet nagging questions remain in the minds of diplomats, bankers and security analysts watching North Korea. Is this the end of Pyongyang's long and strange marriage of convenience with Macau? How will North Korea carry out its foreign trade banking now, given the US Treasury's crackdown? What will happen to Banco Delta Asia?

Well-placed Asian and western diplomatic sources say Macau has always been far too important to Pyongyang - and the ties too deep - for it to just pack up and go home.

The relationship flourished in the mid to late 1970s when the new Portuguese government formally recognised North Korea after Lisbon's left-wing revolution of 1974.

At its height, North Korea ran trading companies in Macau, staffed by North Koreans with diplomatic passports. Dozens of trading staff, unofficial diplomats and spies exploited the network, headed by its long-established Zokwang Trading Company operating from an office on the Avenida Sidonio Pais. Weekly Pyongyang-Macau-Bangkok flights by North Korean passenger jets ended in 2005.

Officially, Zokwang has traded rubber, cloth and ginseng. It has also been linked to other, darker, commodities. Its five top officials were arrested in 1994 for attempting to deposit US$250,000 in counterfeit currency. They were later released.

As US pressure intensified with the treasury's September 2005 declaration that Banco Delta was a 'willing pawn' in three decades of North Korean crime, the network was rolled up.

Diplomatic sources note, however, that it has simply moved to Zhuhai and Shenzhen, with about 15 companies re-establishing themselves and using existing bank accounts. Their representatives are frequent travellers to Macau, but struggle to gain visas for Hong Kong.

'They're still involved in Macau, they have just moved, that's all,' said one long-time North Korean watcher. 'It's North Korea's playground ... it's simply too important for them to let go.'

The companies source luxury goods shipments to the Stalinist regime of Kim Jong-il and have also been linked to sourcing various electronic devices.

Kim Jong-nam, Mr Kim's eldest son and potential heir to communism's only dynasty, continues to keep a house and family in Macau.

He's been travelling since his three-year presence was exposed this year. He's expected to return soon, however, as the Banco Delta issue cools.

'Kim Jong-nam has told his friends it's one of the few places he can relax and live normally, free of the baggage or pressures he would face in bigger capitals,' one Macau source said. 'It's the same for his country. Macau is the place where they can fly beneath the radar ... it still remains important to them.'

The links to Banco Delta Asia appear all but severed, however. While North Korea may have pulled off a diplomatic coup by getting its money despite US concerns about the illicit nature of some of the cash, the bank has had no such luck.

A formal treasury blacklisting barring Banco Delta Asia from any connection to the US financial system took effect in April. The move has effectively cut it out of the international financial system - highlighted by the struggle to move the unfrozen funds out of Macau.

It remains under the control of Macau government-appointed receivers. Banco Delta Asia and its owner, Stanley Au Chong-kit, whose family set up the privately held bank in 1953, are legally challenging the treasury's actions.

Mr Au has previously cited an Ernst & Young study commissioned by Macau's banking authorities. The report, revealed by the Post in April, cleared the bank of counterfeiting allegations, but exposed a host of management shortcomings across its trade with North Korean companies and individuals. A lack of information and clear procedures prevented firm conclusions on allegations of money laundering for North Korea, it noted.

Mr Au has declined interviews. Macau banking sources say he's determined to keep the bank, describing it as a family jewel, despite US pressure for a change of ownership. He's also confident that Beijing can work to have the blacklisting lifted, sources say. China has formally expressed its concern to Washington over the move.

'The issue is rapidly moving beyond Macau, but Banco Delta Asia remains in the soup,' said Bradley Babson, a North Korea analyst and former World Bank official. 'What happens to Banco Delta now is one of the big unanswered questions of this whole case.'

Mr Babson said it was also hard to tell how North Korea would be able to run its regular trade through the international banking system.

'It does seem the US intends the transfer to Russia to be a one-off. It's going to be very interesting to see whether international banks are now prepared to deal with North Korea after all this,' he said. 'What will be North Korea's new Macau? Will it use this saga to try to reform and improve its links with the outside world? It's hard to tell at this point, but both are very important points as we try to move forward.'

It also remains unclear what more the administration of US President George W. Bush hopes to achieve with its financial crackdown - an effort launched earlier in the decade but quickly taken over by the political pressures of a nuclear test.

As the dust settles, observers say it's clear that Washington used the crackdown for a complex set of ends. Initially, it wanted to protect its currency, squeeze North Korea and stop it spreading weapons, while also cleaning up a Macau that is attracting unprecedented US investment through its casino boom. Then came the diplomatic pressure to get Pyongyang back to the nuclear bargaining table. 'Macau has come to represent a new great game in US policy,' one diplomat said. 'It may not be over yet and we know there are debates within the US administration.' Many loose ends remain.

The return of the funds has alarmed former State Department official David Asher, who was involved in the crackdown from the outset. 'Even as a diplomatic act of expediency, this strains one's litmus test of what is reasonable and contradicts the spirit, and possibly the letter, of laws we have invoked and international agreements we have vociferously supported,' he told the US Congress in April.

Far from the Banco Delta case being settled, Mr Asher said 'the reality is that its effects will linger until North Korea demonstrates that it can ... operate as a normal, transparent, rule-abiding member of the international financial system'.