G20 warns over 'loopholes'

More needs to be done to combat "loopholes and deficiencies" in the world financial system as part of the fight against terrorism, finance ministers from the G20 group of leading economies said Saturday.

In a communique following a meeting in Shanghai, the G20 officials urged the Paris-based Financial Action Task Force (FATF) to "intensify its work on identifying, analysing and tackling terrorist financing threats, the sources and methods of funding and the use of funds".

The ministers were "resolved to combat decisively terrorist financing" and would intensify efforts to tackle "all sources, techniques and channels of terrorist financing", they said, pledging to enhance cooperation and information exchange.

The promises -- which did not include precise details -- came after the head of the FATF said some government responses were still inadequate in the fight against money laundering, terrorism financing and other threats.

Since the Paris terror attacks in November, when 130 people were killed, around 50 countries have responded to a new call by the FATF -- whose current blacklist includes North Korea, Afghanistan and Syria -- for concrete steps to choke terror organisations funding, the body's executive secretary David Lewis told AFP.

Meanwhile, finance ministers from the world's leading economies yesterday warned of a "shock" to the global economy if the UK leaves the EU.

The ministers give their assessment in a statement released at the end of a two-day meeting of G20 nations in China.

UK Chancellor George Osborne, who is at the event, told the BBC the issue was "deadly serious".

The UK will vote on whether to leave or remain in the EU on 23 June.

Meanwhile, London Mayor Boris Johnson has clarified his position on the idea that a vote to leave the EU could force Brussels to give Britain a better deal and trigger a second referendum.

Johnson had previously suggested that only by voting to leave would the UK "get the change we need".

But in The Times, Johnson stated categorically: "Out is out".