The US and UK have simultaneously frozen the assets of an Islamic charity which they say is funding terrorist activities.
Islam requires Muslims to give alms, or zakat
The Al-Aqsa Foundation, officials said, feeds money to Hamas, one of the groups which sponsor suicide bombings on civilian targets in Israel.
"Today's action, taken in co-ordination with our international allies, will ensure that no UK funds belonging to the Al-Aqsa Foundation can be used to support terrorism," said UK Chancellor of the Exchequer Gordon Brown.
The timing - immediately before a trio of meetings between President George W Bush and Middle Eastern leaders next week - was purely coincidental, US Deputy Assistant Treasury Secretary Juan Zarate told reporters.
But he went on: "It's a clear signal the US takes very seriously the rejectionist stance of Hamas and other likeminded terrorist groups that are impeding, in our mind, the peace process."
The action is the latest in a series of restrictions imposed by US and UK authorities on some Islamic charities, which they charge are funnelling money to terrorists.
Zakat, or alms-giving, is an obligation on practising Muslims, and Islamic charities - often linked to particular mosques - are active wherever there are Muslim communities.
But a number of charities accused of financing terror, including the Global Relief Foundation and Benevolence International, have been closed, while some senior charity staff members have been arrested.
Chain of closures
It remains unclear exactly how much money is in Al-Aqsa bank accounts in the UK and US.
But the shutdown is only the latest in a string of closures of Al-Aqsa Foundation operations in Europe.
Earlier this year, Denmark and the Netherlands banned the local branches, while its German operations were shuttered in August 2002.
The phone number for an office in Brussels is now unobtainable, BBC News Online found.
The US and UK say it has other operations in Sweden, South Africa, Pakistan and Yemen.
The action takes to 264 the number of individuals and groups on the US Treasury's list of asset freezes, and the amount frozen since 11 September 2001 to about $137m.
Follow the money
That money raised by Al-Aqsa goes to Hamas is not in doubt.
The foundation's defenders maintain that the money is spent on Hamas' social activities. The organisation has organised healthcare, education and food distribution across much of the Occupied Territories.
But the US and UK governments insist that the money - with Al-Aqsa's knowledge and consent - goes to fund suicide bombers and other armed activities by Hamas.
The Israeli government has long accused Al-Aqsa of being one of four charitable groups responsible for keeping Hamas afloat, alongside contributions from Middle East charitable bodies and Gulf state governments, as well as from legitimate business activities in the West Bank.