Now, Israel’s planned ground offensive in the southern Gaza city of Rafah is heightening those tensions, at a time when hundreds of thousands of Palestinians fleeing months-long Israeli bombardment have sought refuge in Rafah.

Egyptian Foreign Minister Sameh Shoukry on Monday denied reports Cairo had any plans to back out of the 1979 peace deal, but added that his country would adhere to the treaty as long as it was “reciprocal”.

Here’s more about why Israel’s Rafah offensive is so critical to the relationship between Egypt and Israel.

Why is Egypt against Israel’s planned Rafah offensive?

Israel’s planned ground assault on Rafah threatens to intensify pressure on displaced Palestinians to move into Egypt’s Sinai – a development Egyptian officials have declared would cross a red line.

The roughly 1.4 million internally displaced Palestinians who have been squeezed into 64sq-km (25sq-mile) Rafah have nowhere to go amid shortages of food, water and medicine. NGOs, governments and other members of the international community have objected to the planned Israeli offensive, fearing large numbers of civilian casualties. Some 100 people, including 42 children, have been killed in Israeli attacks since Sunday night.

Since Israel launched its war on Gaza on October 7, calls by senior Israeli officials for the Palestinians to emigrate from Gaza – a euphemism for their forced displacement – have alarmed Egyptians who do not want a refugee exodus across the border. Egypt, as well as several Arab countries, fear that Israel will not allow displaced Palestinians to return to Gaza.

More than 750,000 Palestinians, who were driven from their homes in the 1948 ethnical cleansing – called the Nakba, or catastrophe, by Palestinians – during the creation of the state of Israel, have not been allowed to return. Israel has consistently opposed the Right of Return to Palestinians driven out of what is now Israel during the Nakba.

Israeli Prime Minister Benjamin Netanyahu’s suggestion in December that he wanted control of the Philadelphi Corridor – a narrow corridor that separates Egypt from Gaza – has also angered Egyptians. Diaa Rashwan, the State Information Service chief said at the time that the “occupation” of the 14-kilometre (about 8.7 miles) long and 100-metre-wide (328-foot-wide) corridor would be a breach of the Egypt-Israel Peace Treaty.

Egypt has controlled the strip of land since Israel withdrew from Gaza in 2005.

Cairo has tightened border security, reportedly moving tanks and armoured personnel carriers close to the border to halt any potential spillover from an Israeli land assault.

Both countries are required by the 1979 deal not to boost their military presence in border areas without prior agreement. Al Jazeera has not been able to confirm if Cairo coordinated its military movement with Tel Aviv.

Israel’s Transportation Minister Miri Regev said that his country was aware of Egypt’s concerns regarding the impending Rafah offensive, adding that Cairo and Tel Aviv would be able to sort out the matter through talks.

What has Egypt’s relationship with Israel looked like?

Egypt-Israel ties have survived several crises in the Middle East including the Palestinian intifadas and Israel’s invasion and occupation of the West Bank and East Jerusalem, as well as its numerous military assaults on Gaza.

Under the leadership of Egyptian President Abdel Fattah el-Sisi, ties with Israel have increasingly focused on economic and energy relations at a time when Cairo is tackling a severe economic crisis.

Since el-Sisi took power in a 2013 coup, Egypt, as part of its security coordination with Israel, has destroyed hundreds of tunnels that Palestinians used to smuggle goods – and at times, weapons – past the Israeli blockade on Gaza. Cairo has also destroyed thousands of buildings to create a buffer zone between Egypt and Gaza. Egypt has cooperated with Israel in the 17-year blockade of Gaza.

Egypt, on Monday, lambasted comments by Israeli officials that Hamas was using its territory to smuggle in arms.

The Egyptian president has spoken out against the widespread destruction of Gaza and the killing of thousands of Palestinians amid widespread support for Palestinians in the country.

For decades, Egypt has played a leading role as a mediator in brokering talks and prisoner swap deals between Hamas and Israel. Cairo is currently hosting Israeli and Hamas officials in an effort to achieve a ceasefire in Gaza. More than 28,000 Palestinians have been killed in the Israeli offensive since October 7. Tel Aviv says its military goal is to destroy Hamas, but it has faced condemnation for the large number of civilian casualties.

What are the Camp David Accords?

Former US President Jimmy Carter brokered a series of peace talks between Egypt’s then-President Anwar Sadat and Menachem Begin, the former Israeli prime minister, at Camp David, a country retreat for the US president near Washington, DC.

The accords laid out conditions for an Egypt-Israel peace treaty, and a framework for Israeli-Palestinian peace using UN Resolution 242, which called for a withdrawal of Israel from territories occupied during the Six-Day War in 1967.

Israel agreed to pull out its forces from Sinai in exchange for diplomatic ties with Egypt and access to the Suez Canal – a major shipping route. Egypt had nationalised the canal in 1956, after which Israel, along with the United Kingdom and France, unsuccessfully invaded Egypt to wrest back control of the canal.

Analysts have said Cairo is unlikely to walk away from the Camp David Accords. Egypt receives billions of dollars of US aid as part of the deal and has close military ties with Washington. A massive military build-up would also strain Egypt’s already struggling economy.