Reports that US singers Beyonce and Jennifer Lopez will perform in Israel this summer have triggered a pre-emptive campaign by activists, who are calling on the stars to boycott Israel in solidarity with the plight of Palestinians.

By Thursday, at least two petitions against Beyonce's rumoured concert date in Tel Aviv had been launched, while social media users attached the #canceltelaviv hashtag to posts as they called on the pair to support a boycott.

Neither of the musicians' websites confirmed reports in Israeli media that their performances would go ahead this summer.

Al Jazeera contacted the management teams for both artists and is yet to receive a response.

"There have been several news stories indicating that Beyonce's management is in final negotiations for a concert in Tel Aviv," Evan Greer, the activist who launched the "Tell Beyonce not to play apartheid Israel!" petition, told Al Jazeera.

"The best thing for Beyonce's management to do would be to publicly clarify that she will not be performing in Tel Aviv, and issue a statement of solidarity with the Palestinian people," Greer added.

'Brutal apartheid occupation'

Others, including the Palestinian-American author Randa Jarrar and the writer and activist Che Gossett, pleaded with the African-American celebrity on social media not to bring her "Formation" tour to Israel.

Greer continued: "Notable musicians like Elvis Costello, The Pixies, Carlos Santana, and Gil Scott-Heron have all cancelled performances in response to calls to join the boycott.

"Each time a major artist like this cancels a show, it brings much-needed international attention to the situation in occupied Palestine."

The documentary film-maker Ronan Tynan, meanwhile, protested about a potential visit by Jennifer Lopez, saying he was "shocked" the 46-year-old "could let herself down so badly backing Israel's brutal apartheid occupation [by] playing Tel Aviv."

I'm wondering if @BlackLivesMpls will urge Beyonce to cancel her concert in Tel Aviv. As a reminder, #BLM met with activists from Palestine. — فيروز (@Zou_Fay) February 10, 2016

In Beyonce's case, many criticised what they called hypocrisy as the African-American celebrity's latest song and accompanying video for "Formation" references racial inequality and the Black Lives Matter movement.

She performed the song, with lyrics about black pride, at the Super Bowl on Sunday alongside dancers dressed in Black Panther-themed outfits.

Hey black folks, especially you "extra woke" lot: can we channel our energy into trying to make sure Beyonce doesn't play in Israel? — Zoe S. (@ztsamudzi) February 10, 2016

"The fact is, the discussions [for the musicians to perform] under way are enough for those that support the Boycott Divestment and Sanctions (BDS) movement to be pushing back hard," Stanley Cohen, lawyer and anti-Zionist activist, told Al Jazeera.

Speaking by phone from New York, he added: "The key thing for BDS, from my position, is that when you begin to see momentum towards someone crossing the line, we have to make sure that they [the artists] understand the issue.

"Once someone signs a contract, they then too often have the excuse that they cannot step out because of financial injuries to family or friends. You don't want to wait until the ink has dried."

Cohen's career has focused on defending rights activists, including clients many believe do not deserve due process.

Sometimes described as a radical lawyer, Cohen was directly involved in talks to win the freedom of US aid worker Peter Kassig, who was later beheaded by the Islamic State of Iraq and the Levant group in Syria.

'Effective' cultural boycotts

"I think BDS is the only effective tool that non-Palestinians have," Cohen said.

READ MORE: Italian scholars boycott Israeli academic institutions

Israeli Prime Minister Benjamin Netanyahu "is always jumping up and down screaming about terrorism", said Cohen.

"When people turn to non-violence, when they bring peaceful political pressure, it's labelled as criminal.

"My position is simple - it's not business as usual. You have to put pressure on the body politic of Israel and hold the leaders accountable, and this is the way."

Both Cohen and petition-leader Greer said that the most positive examples of successful boycotts can be found in South Africa's history, with many movements launched to support non-whites during apartheid.

"Cultural boycotts have been incredibly effective in raising global awareness of severe human rights abuses, land theft, and genocide," said Greer.

"The cultural boycott of apartheid South Africa was a significant part of the movement that eventually ended it."

Follow Anealla Safdar on Twitter: @anealla