As Israel devastates Gaza, Egypt has largely had to watch on with rising concern about the developments on its border.

Its border with the Palestinian enclave has been a route for aid going in and people coming out but Israel has had the ultimate say over access to the border, even if it did not have a physical presence there until last week.

And it was that move – to send Israeli troops to the Rafah border crossing – that experts believe has cemented Egypt’s belief that Israel is not taking its security and political concerns seriously, and is instead “disrespecting” them.

Egypt has now taken its own steps – on May 12, the Egyptian Ministry of Foreign Affairs confirmed that Egypt had joined South Africa’s International Court of Justice (ICJ) genocide case against Israel.

“The significance of this move is that it is sending a signal that Egypt is not happy with what’s happening in Gaza and how Israel is behaving,” said Nancy Okail, an expert on Egypt and the president and CEO of the Center for International Policy, even as she downplayed the effect of Egypt’s decision on the ICJ’s final verdict, labelling it a “symbolic gesture”.

Egypt has grown increasingly alarmed with Israel’s military operations in Rafah, where about 1.5 million Palestinians from all over Gaza had sought refuge.

The takeover of the Philadelphi Corridor, which separates Egypt from Gaza, is particularly worrying for Cairo; the Egyptian parliament has warned that the Israeli military’s presence there was a violation of the Camp David Accords that brought peace between Egypt and Israel.

“The way Israel has acted in the last week and a half has been incredibly troubling for Egyptian officials,” said Erin A Snyder, a scholar of Egypt and a former professor at Texas A&M University. “They have been effectively showing disrespect for the relations that they have [with Egypt].”

Red lines crossed?

The possibility that Israel’s ultimate goal in Gaza is to force out its Palestinian population has worried Egypt since the beginning of the war in October.

Early on, Israel’s intelligence ministry drafted a paper that proposed the transfer of Gaza’s 2.3 million people to Egypt’s Sinai Peninsula. Although the Israeli government downplayed the report, Israeli politicians, including the far-right duo of Finance Minister Bezalel Smotrich and National Security Minister Itamar Ben-Gvir, said they supported the “voluntary” migration of Palestinians from Gaza.

The repeated suggestions have set off alarm bells in Egypt, which views any such transfer of millions of Palestinians into its territory as a red line that cannot be crossed, and President Abdel Fattah el-Sisi has warned Israel against any such move.

“Egypt has been sounding the alarm on the destabilising prospects of an Israeli military operation in Rafah and on any military action that could result in the alleged resettlement plan that emerged out of Israel last fall,” said Hesham Sallam, a scholar on Egypt and the Middle East at Stanford University.

Israel has seemingly taken measures to assuage Egypt’s concern by instructing Palestinians in Rafah to evacuate to al-Mawasi, a coastal area to the west of Rafah, away from Egypt.

Israel claims that al-Mawasi is a “safe humanitarian zone”, but aid groups say tens of thousands of people are crammed into the area without access to adequate food or water.

Over the last week, 450,000 people have fled Rafah, according to the United Nations, and nearly a million remain.

“The Israelis are intent on wrapping things up in Rafah in a way that looks similar to what they did in Khan Younis, or at least eventually,” said H A Hellyer, an expert on Middle East geopolitics at the Carnegie Endowment for International Peace and the Royal United Services Institute.

“That is deeply concerning to Cairo because they don’t want more escalation along the border.”

Dead end talks?

Egypt has hosted ceasefire talks between Hamas and Israel, playing a critical role in mediating between the two sides, along with Qatar and the United States.

However, Egypt seems frustrated with Israel’s refusal to end the war in exchange for the release of Israeli captives held in Gaza, according to Timothy Kaldas, an expert on Egypt and deputy director of the Tahrir Institute for Middle East Policy think tank.

“The Israelis didn’t seem to take the ceasefire talks that Egypt was hosting seriously … and it’s not clear to anybody what would get Israel to agree to a ceasefire,” he told Al Jazeera.

“Egypt is probably pretty frustrated that this conflict has no end in sight.”

Two days before Israel stormed into eastern Rafah, Egypt, Qatar and the US lobbied Hamas and Israel to sign a deal. Hamas agreed to a modified version of the ceasefire proposal presented at the talks, but Israel rejected it.

Days later, Egyptian military officials cancelled a planned meeting with Israeli counterparts due to their disagreement over the Rafah operation, according to the Israeli press. “We don’t know what the meeting was supposed to be about. But certainly this move  –  overlapping with [joining the ICJ case] – is an indication that there is a great deal of frustration with Israel from the Egyptian side,” Sallam said.

Another delegation of Israeli intelligence officials is said to have arrived in Cairo on Wednesday for talks with their Egyptian counterparts over Rafah.

Peace treaty in danger?

Egypt has little leverage left beyond suspending its peace treaty with Israel, a move experts believe is unlikely. That step could jeopardise the $1.6bn in US military assistance Egypt receives annually as part of the peace agreement.

“I generally doubt that there is any serious risk to the Camp David Accords,” said Kaldas. “The Egyptians benefit in a number of ways from maintaining that agreement.”

Snyder said “anything is possible”, noting that everything Israel is doing in Gaza is unprecedented. However, she does not expect Egypt to suspend the treaty either, as it is central to US regional interests.

“I feel that the US is very concerned and is working to ensure that [suspending the treaty] doesn’t happen,” she told Al Jazeera.

Snyder added that Egypt’s decision to join South Africa at the ICJ should also be seen as an attempt to pressure Israel’s strongest ally and largest weapons supplier to take action on regional security.

“This isn’t just about pressuring Israel. It’s also about pressuring the US to use its leverage towards Israel,” she told Al Jazeera.