(Adds comment from Islamic charity)
JERUSALEM, June 19 (Reuters) - Israel on Thursday banned a British-based charity from operating in the occupied West Bank, accusing Islamic Relief Worldwide (IRW) of being a source of funding for the Palestinian Hamas Islamist movement.
Israel has intensified its crackdown on Hamas, through raids on its West Bank institutions and arrests of suspected activists, after accusing the group of abducting three Israeli teenagers who disappeared near a Jewish settlement a week ago.
Defence Minister Moshe Yaalon signed an order declaring the IRW an "unauthorised association" and empowering Israeli authorities to seize any funds the group might send to Palestinians in the West Bank, his ministry said in a statement.
IRW said it had not been directly told of any sanctions against it but issued a statement on its website http://www.islamic-relief.com/ saying it was "surprised and extremely concerned" at the media reports.
"Islamic Relief Worldwide has heard nothing about this decision from the Government of Israel or any official sources. All we know is what has been reported in the media," it said.
Yaalon said in the statement that some of the charity's chapters, including those in the West Bank and Gaza Strip, were run by Hamas members.
"The IRW is one of the sources of Hamas's funding and a means for raising funds from various countries in the world," he said. "We do not intend to allow it to function and abet terrorist activity against Israel."
Hamas is designated a terrorist group by Israel, the United States and European Union. It has charitable networks as well as armed cadres, contributing to its popularity among Palestinians.
According to IRW's website, it has been working in the Palestinian territories since 1994, tending to underprivileged, malnourished and traumatised children as well as creating jobs and encouraging entrepreneurship with interest-free loans.
Founded in 1984, IRW lists the European Commission, the World Health Organization and UNHCR - the UN Refugee Agency - among its "key partners".
There has been no word from the missing teenagers since their disappearance, nor any public claim of responsibility or ransom demands, including by Hamas, though neither has it denied involvement. (Writing by Dan Williams; Editing by Louise Ireland)