LONDON (AFP, REUTERS, BLOOMBERG, NYTIMES, WASHINGTON POST) - Britain's overseas aid minister Priti Patel has resigned over talks with the Israeli government behind Prime Minister Theresa May's back after more revelations of undisclosed visits came to light.

Ms Patel had met Mrs May on Monday (Nov 6) and apologised for the unauthorised talks during a family vacation in August, where she held meetings with a dozen Israeli leaders, including Prime Minister Benjamin Netanyahu, without notifying the British Embassy in Tel Aviv or the Foreign Office in advance.

But it emerged late on Tuesday there had been another two unauthorised meetings in September, with Israel's Public Security Minister Gilad Erdan in London and senior foreign ministry official Yuval Rotem in New York.

Ms Patel, a Brexit campaigner who is popular in the ruling Conservative Party, had to abandon a trip to Africa earlier on Wednesday after being summoned by Mrs May following the new revelations.

After a hastily arranged meeting not long after Ms Patel landed in London, Mrs May's office released her minister's letter of resignation, in which Ms Patel said her conduct in Israel had fallen "below the high standards" required of her post.

"While my actions were meant with the best of intentions, my actions also fell below the standards of transparency and openness that I have promoted and advocated," Ms Patel wrote in the letter to Mrs May.

"I offer a fulsome apology to you and to the government for what has happened and offer my resignation."

Ms Patel wrote in her letter that there had been a "number of reports about my actions and I am sorry that these have served as a distraction".

In reply, Mrs May said in a letter to her: "Now that further details have come to light, it is right that you have decided to resign."

Mrs May was expected to appoint a new aid minister on Thursday.

On Monday, Ms Patel revealed details of her meetings in Israel, which included discussions with non-governmental organisations and businesses.

She said they were arranged by Lord Stuart Polak, honorary president of the lobbying group Conservative Friends of Israel. According to news reports, Lord Polak sat in on 11 of the 12 meetings, including the one with Mr Netanyahu.

During her meetings, Ms Patel discussed the possibility of British aid being used to support medical assistance for Syrian refugees arriving in the Israeli-occupied Golan Heights, Downing Street said.

However, reports suggest that she did not explain to Mrs May that this involved supplying funding to the Israeli army, which has helped treat more than 3,100 wounded refugees in Israeli hospitals since 2013.

Britain views the Golan Heights as occupied territory and a minister told MPs on Tuesday that funding the Israeli Defence Forces there was "not appropriate".

A senior Palestinian official on Wednesday condemned the meetings as "scandalous", urging Mrs May to take action.

In a further development on Wednesday, Israel's Haaretz newspaper reported that Ms Patel visited a military field hospital in the Golan Heights as a guest of the government. The British aid ministry declined to comment on the report.

The daughter of Ugandan Indians, the 45-year-old Ms Patel has been an MP since 2010. Her political idol is Mrs Margaret Thatcher, who served as prime minister from 1979 to 1990 and died in 2013.

Ms Patel suggested in her resignation letter that she is unlikely to let herself fade into obscurity now that she's been relegated to the back benches.