LONDON (Reuters) -More than 10 Britons are feared dead or missing in Israel, the BBC reported on Monday, citing an official source, although foreign minister James Cleverly said he would not speculate on the number of British or dual nationals in the area.

Britain's Foreign Office declined to comment on the report.

When asked about the number of British or dual British-Israeli nationals either dead or missing, or in Israel and the occupied Palestinian territories, Cleverly told reporters:

"The nature of Israeli citizenship means that there are a significant number of dual British-Israeli nationals, many of whom will have made their permanent home in Israel, many of whom will be serving with the Israeli defence force.

"So it's not possible for us to give numbers and I do not intend to speculate."

Islamist group Hamas killed 700 Israelis and abducted dozens more in a surprise attack on Saturday.

A London-born man who was serving in the Israeli army died on Saturday on the Gaza border, his family said, and another British man was missing, Israel's embassy in London said on Sunday.

(Reporting by William James, writing by Sarah Young; Editing by Kate Holton)