Israeli prime minister Benjamin Netanyahu has cancelled a meeting with the visiting German foreign minister over the latter's plans to hold a meeting with Israeli rights groups.
An official said Mr Netanyahu was upset that German foreign minister Sigmar Gabriel is sitting down with Breaking the Silence, a whistleblowing group critical of Israeli military actions in the West Bank.
Earlier in the day, Mr Gabriel said it would be "regrettable" if the meeting was cancelled.
The cancellation marks a rare diplomatic feud between Israel and one of its closest and most important allies.
The last-minute decision cast a cloud over a visit that had been meant to draw attention to years of friendship between the two countries and coincided with Israel's annual Holocaust memorial day.
Asked about a possible cancellation earlier, Mr Gabriel said it would not be a "catastrophe". He said: " I have been in this country so often and have a lot of friends, and it wouldn't change my relationship with Israel.
"You can't get a proper and comprehensive picture in any country on Earth if you only meet in government offices," he added.
"I can't imagine that we would not do such things in the future just to get government appointments."
Mr Gabriel has been Germany's foreign minister since January and its vice chancellor since 2013. This is his first visit to Israel in the new job.
Breaking the Silence is a group of former Israeli combat soldiers opposed to Israel's nearly 50-year occupation of the West Bank. The group publishes testimony, often anonymous, about what former soldiers say is the dark underbelly of service in the Palestinian territories.
Israeli leaders oppose the group's work, citing the anonymity of the claims and its outreach efforts to foreign audiences. They say there are better, more legitimate ways to criticise the army.