Sotto voce criticism of the Philadelphia Orchestra's upcoming tour of Israel began a few weeks ago, but erupted noisily Friday with about four dozen protesters rallying in front of the Kimmel Center as audiences were leaving an orchestra matinee.

Activists urged the orchestra to cancel its concerts in Haifa, Tel Aviv, and Jerusalem, citing Israel's treatment of Palestinians in general and, in particular, recent actions by Israeli security forces at Gaza border demonstrations that left more than two dozen Palestinians dead and hundreds injured.

"Tune out Apartheid — Don't Fiddle for Israel," read one sign. "Violins — Not Zionist Violence" was another.

The orchestra said it won't be changing its tour. "Absolutely not," said interim co-president Ryan Fleur. "We were advised when we first started planning that there will be people who don't want us to go to Israel, and people will make it known, so this is no surprise to us."

Activists began asking the orchestra to cancel its Israel dates a few weeks ago, and said their requests to meet were rebuffed.

"A global cultural boycott helped end apartheid in South Africa, and now Palestinian civil society has called on international cultural institutions not to perform in Israel to help pressure Israel to end its policies of occupation and apartheid," stated a letter to music director Yannick Nézet-Séguin and other orchestra leaders, bearing at its bottom the names of dozens of musicians, clergy, activists, and others from Philadelphia and around the globe.

Organizers cite artists like Elvis Costello and Lorde as having canceled concerts in Israel — some as part of the boycott, divestment, and sanctions (BDS) campaign — and the protesters in Philadelphia are pressuring the orchestra to join the movement.

Fleur says the orchestra's visit is about "people-to-people cultural diplomacy, because Israel has a lot of classical music lovers." In addition to the musical value of the concerts, the orchestra has said the visit will help it bond with Jewish patrons and donors.

The orchestra, he said, does not enter into politics. "We don't take political positions on China, on Israel, or Mongolia," where the orchestra has also toured. "As soon as we engage in any political dialogue, we lose our purpose," he said.

But Susan Abulhawa, a Philadelphia writer representing the protest group, said that the orchestra, by "their presence there, it does harm. They claim it's not a political mission, but they say they are going to celebrate Israel's 70th anniversary. They have also planned their itinerary in consultation with the Israeli government. They have on their itinerary meetings with high-level government officials."

Abulhawa cites a meeting the orchestra has planned with Miri Regev, a controversial far-right Israeli politician and minister of culture and sport. The website of the Jewish Federation of Greater Philadelphia, the orchestra's partner in the Israel trip, describes the patron tour accompanying the orchestra as starting with a June 1 Shabbat welcome dinner at which Regev, as well as Tel Aviv Mayor Ron Huldai, are invited guests.

The orchestra's patron tours are for a group of donors, board members, and fans who accompany the ensemble for concerts but branch off on their own during the day for other activities. The patron tour itinerary for June 3 lists a lunch reception with Israeli President Reuven Rivlin "and other invited dignitaries."

Naomi Adler, president and CEO of the federation, said that no invited guests were confirmed so far, and that diplomacy was about talking to people with whom you disagree as well as agree. "The BDS movement is trying to impede all kinds of relationships, and we actually believe it is essential for people of all beliefs and mindsets to interact with Israel, to learn what's going on, to get to know the people," said Adler.

About 50 patrons have committed to going on the tour, she said.

One of the signees of the letter urging the orchestra to not visit Israel, the Irish composer Raymond Deane, said in an email that the presence of foreign artists in Israel is meant to "normalize" the abnormal, "which is to say the oppression of Palestinians. … If the Philadelphia Orchestra goes to Israel in violation of the Palestinian boycott call, it will be thumbing its collective nose at the oppressed."

Fleur noted that a group of musicians from the orchestra will be working with and performing for Palestinian students at Beit Almusica, a school in the Israeli city of Shefa'amr.

The Israel leg of the orchestra's tour comes after concerts in Europe, and ends in Jerusalem June 5 with Tchaikovsky's Symphony No. 4 and Bernstein's Symphony No. 2 for Piano and Orchestra, a work that carries the subtitle "The Age of Anxiety."