LONDON (Reuters) - A British court issued an arrest warrant for former Israeli foreign minister Tzipi Livni on war crimes charges but withdrew it on finding she had canceled a planned trip to Britain, the Guardian newspaper reported.

Israel's Foreign Minister Tzipi Livni attends the weekly cabinet meeting in Jerusalem February 22, 2009. REUTERS/Ronen Zvulun

Westminster magistrates court issued the warrant at the request of lawyers acting for Palestinian victims of fighting in Gaza earlier this year, the paper said in an article published online on Monday.

The warrant was later dropped after it was realized that Livni -- who had been due to address a meeting in London last weekend -- was not in Britain.

Human rights groups and U.N. investigators accuse Israel of war crimes in the Gaza Strip during a 22-day offensive against Hamas-led Islamist militants in which Palestinians say more than 900 civilians died -- a figure Israel disputes.

Livni, who is head of the opposition Kadima Party, played a key role in launching the offensive.

The Foreign Office told Reuters it was “looking urgently at the implications of this case.”

“The UK is determined to do all it can to promote peace in the Middle East and to be a strategic partner of Israel,” a spokeswoman said. “To do this, Israel’s leaders need to be able to come to the UK for talks with the British government.”

The justice ministry said it would not comment on individual cases and the interior ministry also declined to comment.

In September pro-Palestinian groups failed to persuade a London court to issue an arrest warrant for Israeli Defense Minister Ehud Barak, whom they also accuse of war crimes.

The court said Barak, who attended the ruling Labour party’s annual conference and met Prime Minister Gordon Brown, had diplomatic immunity.