Sources said about $3.2bn of assets belonging to the Libyan Investment Authority and other entities had been frozen in London, and that figure may go far higher in coming days. The UK initially froze about £1bn in assets linked to the Libyan leader and his children.
It was initially unclear whether the UK government would also target the LIA, which is estimated to control assets worth more than $60bn. On Thursday, Tim Geithner, US Treasury secretary, said Washington had seized nearly $32bn in Libyan assets including those held by the LIA.
Barack Obama, the US president, described the US measures as the ??most rapid and forceful set of sanctions that have ever been applied internationally?.
HSBC, the UK??s largest bank and the LIA??s custodian, holds much of the cash and assets affected by the UK measures, according to people familiar with the sanctions.
Other frozen LIA investments include the fund??s £226m stake in Pearson, owner of the Financial Times, and a £300m property portfolio in London.
In Vienna, authorities questioned Mustafa Zarti, deputy head of the LIA, and froze his assets and accounts. Mr Zarti was later released.
Mr Zarti is a close associate of Seif al-Islam, Colonel Gaddafi??s son, who exercised considerable influence over the fund.
The Austrian foreign ministry said a directive, issued on February 25, provided the legal basis for asset freeze, adding that there appeared to be ??some sort of closeness between Mr Zarti and the Gaddafi family ?? there seems to be enough evidence for that?.
The government in Vienna will press the European Commission to add Mr Zarti to the European Union??s list of 26 Libyans subject to sanctions.
In the UK, government sources said that the Land Registry would notify the Treasury automatically if the LIA sought to undertake any transactions involving its property portfolio.