Hamas and other militant groups in Gaza, claiming to be defending Jerusalem, have fired hundreds of rockets at Tel Aviv and other cities.
Israel has responded with air strikes targeting police and security installations, although the Palestinian authorities said there have been civilian casualties.
It is the worst fighting in the region since the 50-day war of 2014.
The latest upsurge in violence has been triggered by tensions in Jerusalem during the Muslim holy month of Ramadan, with clashes at a holy site sacred to both Jews and Muslims.
The death toll in Gaza has risen to 69 Palestinians, including 16 children and six women. A total of seven people have been killed in Israel.
It’s the latest conflict in a long and complex history between the two sides, one that cannot be neatly summarised in just one article, and a nuanced and fraught historical dispute that experts have spent decades attempting to solve.
But what is Hamas? And what part does it have to play in the recent history of the dispute? Here are the basics.
What is Hamas?
Hamas is the Islamist paramilitary organisation that controls the Gaza Strip, a stretch of land along the Mediterranean coast formed in 1967 when Israel moved Jewish settlements and troops into Gaza.
Israel initially controlled the area until it withdrew in 2005, triggering an election which Hamas won -since then, Israel and Hamas have engaged in several wars.
The organisation was founded in 1987 in response to the ‘First Intifada’, a sustained series of Palestinian protests and violent riots in the West Bank, Gaza Strip and within Israel against the Israeli occupation of the West Bank and Gaza that had begun twenty years prior.
Hamas’ origins can be traced back to the Egyptian Muslim Brotherhood which had been nonconfrontational toward Israel, and hostile to the Palestine Liberation Organisation (PLO); Hamas sought to flip those attitudes around.
Sheik Ahmed Yassin, one of Hamas’ many co-founders, said the organisation was founded as a means to liberate Palestine from Israeli occupation, and to establish a Palestinian state based on Islamic values in the area that is now Israel, the West Bank and the Gaza Strip.
Many countries including the US and the European Union recognise Hamas as a terrorist organisation, but the UK does not.
Instead, the UK only considers Hamas’ military wing – the Izz ad-Din al-Qassam Brigades – as a terrorist organisation. The group also has a social service wing, called Dawah.
Hamas' current leader is 69-year old, Ismail Haniyeh.
How did Hamas come to power?
Hamas won a clear victory in the vote for the Palestinian parliament in 2006, with voters seeing the organisation as an alternative to the long-ruling Fatah party, the main party of the PLO.
Fatah was thought to be a corrupt political party, and had failed to make good on its promises to take Palestine to internationally recognised statehood while improving the conditions of its people.
Hamas also uses its Dawah social services arm to stregnthen health, education, and social services in the West Bank and the Gaza Strip, allowing its popularity to grow despite a policy of suicide bombings and rocket attacks on Israeli civilians.
Hamas secured 74 of 132 parliamentary seats in the 2006 election, and originally offered Fatah the chance to join a coalition.
Fatah refused, and though a short-lived government agreement was orchestrated by Saudi Arabia, this soon fell apart under pressure from both Israel and the US, leading to civil war between the two parties.
Hamas emerged the victor of that particular conflict (just one of many in the two sides’ – and two contested areas’ – complex histories), and expelled Fatah officials and members from the Strip, becoming the sole governing power in Gaza.
What has Hamas done in the past?
Both the actions of Hamas and Israel have been condemned throughout the conflict, with Human Rights Watch classifying both sides’ attacks on civilians as war crimes and crimes against humanity.
“Laws-of-war violations by one party to a conflict do not justify violations by another,” it said in a 2009 report, “and reprisal attacks that target civilians are prohibited under any circumstances.”
Hamas has in the past launched attacks against Israeli civilians and soldiers, claiming many of its attacks to be retaliatory for the assassinations of prominent leadership figures.
A message from the editor:
Thank you for reading. NationalWorld is a new national news brand, produced by a team of journalists, editors, video producers and designers who live and work across the UK. Find out more about who’s who in the team, and our editorial values. We want to start a community among our readers, so please follow us on Facebook, Twitter and Instagram, and keep the conversation going.