"There is no justification for the closure of the Rafah crossing," Hamad al-Raqb, a spokesman for the protesters, said in a speech marking the beginning of a four-day sit-in.
"It is unbecoming of the historic relations between Egyptians and Palestinians," he insisted.
Leading Hamas figures and MPs attended the launch ceremony.
Egyptian authorities have tightened their control over the border with the Hamas-run Gaza Strip since last July's ouster of elected president Mohamed Morsi by the Egyptian army.
In recent weeks, Egypt has repeatedly closed the Rafah crossing, which – due to an ongoing, eight-year Israeli siege – represents Gaza's only window to the outside world.
The Egyptian army has also launched a campaign aimed at destroying the network of tunnels linking Gaza to Egypt's Sinai Peninsula, which in recent years had been used to bring vital commodities into the besieged coastal enclave, home to nearly 2 million Palestinians.
Hamas, an ideological offshoot of the Muslim Brotherhood, the group which propelled Morsi to power in the 2012 elections, has controlled the Gaza Strip, since 2007.
Mauritania hosts the two-day Arab summit for the first time
Article in The Atlantic claims Turkey has 'no democracy for it to lose'
Co-chair of Turkish/EU lawmakers' committee says Europe should prevent Gulen Organization's activities
Graham Fuller, a former CIA chairman has refuted claims that Fethullah Gulen was the mastermind of the coup. Gulen fled Turkey to the US in 1999 after officials charged him with trying to overthrow the state
Assault rifles and heavy weapons used in South Sudan were sold by a Polish millionaire involved in illegal arms sales
Taiwanese nationals in Greece have been arrested for a telecom gambling ring
Right wing Hungarian PM has said that for the EU and Hungary, Trump is the "better option"
Police say 'obvious link' between Munich gunman and Norway's Breivik
The presence of French troops has been a cause of contention and now militia are calling for people rise up against French troops
Angela Merkel has convened her security council over the Munich shootings
Irish leaders have come together to urge the borders to remain open despite the UK voting to leave the EU
Clinton says Virginia senator is 'a man who's devoted his life to fighting for others'
Turkish President Erdogan has for years strengthened his relationship with the masses and with people's trust in him enabled the coup to be around in only a few hours
Despite Israel illegally occupying the land of Palestine, a small group of Palestinian villages living in the hills of al-Khalili may also be forced to leave their homeland because of Israeli claims of living on an "archaeological site"'
Tighter rules and a blacklist of tax havens will be set up to crack down on multinational companies
Nearly 1,000 athletes from 36 countries will compete in the first Down Syndrome Olympics