The Palestinian militant group Hamas launched an unprecedented attack on Israel on 7 October, killing more than 1,400 people and taking more than 200 hostage.
Palestinian health officials say more than 4,000 people have been killed in Gaza since Israel launched retaliatory air strikes, and a ground offensive is expected.
What has been happening in the Gaza Strip?
The first trucks carrying aid into Gaza crossed the border from Egypt on Saturday following days of negotiations.
Israel agreed to allow around 20 trucks carrying food, water and medicine into Gaza through the Rafah border crossing. It was not immediately clear how long the crossing would stay open for.
It comes after the UN’s agency for Palestinian refugees warned that time was running out to get aid into the Gaza Strip.
UNRWA said access to clean water was severely limited and “concerns over dehydration and waterborne diseases are high”.
Israel had said it would not end the “siege” until Hamas released hostages. On Friday, Hamas released two US hostages, the first captives released since the gunmen raided Israel two weeks ago.
Gaza’s Hamas-run government said 18 Christian Palestinians were killed in an explosion within the compound of the Saint Porphyrius Church in Gaza City on Thursday night. The BBC has not been able to verify this figure.
Israel said its jets were targeting a Hamas launch site for rockets and mortars and that a wall of the church was damaged.
Palestinian officials said at least 471 people were killed by an explosion at the Al-Ahli Arab hospital in Gaza City on 17 October. The Israel Defense Forces (IDF) said this number has been deliberately inflated, but has not released its own assessment of how many died.
Hamas blames an Israeli air strike, but the Israeli military said the blast was caused by a failed rocket launch by Palestinian Islamic Jihad (PIJ) and point to the absence of a large crater or blast damage to adjacent buildings. PIJ has denied responsibility.
Will Israel invade Gaza?
Israel’s stated goal is to destroy Hamas.
Israel has massed tens of thousands of soldiers on its borders with Gaza, along with tanks and artillery. It has activated some 300,000 reservists alongside its standing force of 160,000.
The Israeli military has prepared for an offensive by dropping bombs on Gaza and targeting Hamas commanders and its control centres.
Hamas is thought to have about 25,000 people in its military arm.
One of Israel’s main targets is expected to be Hamas’s vast labyrinth of underground tunnels beneath Gaza, which contain bunkers for leaders and command and control centres. It is thought some of the hostages could be held in the tunnels.
Hamas has previously claimed the tunnels stretch for 500km (310 miles). Many have entrances hidden within houses, mosques, schools and other public buildings.
Israel’s troops are likely to avoid going into tunnels unless they have to, instead using explosives to destroy them.
It is thought that Hamas will lay booby traps and improvised explosive devices at entry points and along narrow streets.
A major challenge for the Israeli troops will be close-quarters fighting in densely populated urban areas.
Israel believes Hamas has about 30,000 fighters, with weapons including automatic rifles, rocket-propelled grenades and anti-tank missiles.
What is Hamas and what does it want?
Hamas is a Palestinian militant group, which has ruled the Gaza Strip since 2007.
The group is sworn to Israel’s destruction and wants to replace it with an Islamic state.
Hamas has fought several wars with Israel since it took power.
It has fired – or allowed other militant groups to fire – thousands of rockets at Israel, and carried out other deadly attacks.
In response, Israel has repeatedly attacked Hamas with air strikes, and sent troops into Gaza during two of the wars. Together with Egypt, it has blockaded the Gaza Strip since 2007 for what it describes as security reasons.
Hamas – or in some cases its military wing, the Izzedine al-Qassam Brigades – has been designated a terrorist group by Israel, the United States, the European Union and the UK, as well as other powers.
Iran backs the group, providing it with funding, weapons and training.
Why did Hamas launch its latest attack?
Hamas’s storming of Israeli communities on 7 October, killing more than 1,400 people, was the most serious cross-border attack Israel has faced in more than a generation, the BBC’s international editor Jeremy Bowen said.
Militants breached the wire that separates Gaza from Israel in multiple places.
Details emerged of a massacre in one Israeli community, Kibbutz Kfar Aza.
Survivors estimate that about 100 people were killed, and many others were taken as hostages. Israeli soldiers told Jeremy Bowen that some of the dead had been beheaded.
Given the resources of Israel’s security services, it was astounding that the attack by Hamas was not anticipated, the BBC’s security correspondent Frank Gardner said.
It came at a time of soaring Israeli-Palestinian tensions.
This year has been the deadliest on record for Palestinians who live in the Israeli-occupied West Bank, which could have motivated Hamas to strike Israel.
Hamas might also have been seeking to score a significant propaganda victory to boost its popularity among ordinary Palestinians.
The capture of Israeli hostages is thought to be designed to pressure Israel to free some of the estimated 4,500 Palestinians held in Israeli prisons.
There is also speculation that the attack was orchestrated by Iran, though Iran’s Supreme Leader has denied his country’s involvement.
What is the Gaza Strip and who lives there?
The Gaza Strip is a 41km (25-mile) long and 10km-wide territory located between Israel, Egypt and the Mediterranean Sea.
Originally occupied by Egypt, Gaza was captured by Israel during the 1967 Middle East war along with the West Bank and East Jerusalem. Israel withdrew its troops and around 7,000 settlers from the area in 2005.
It is home to about 2.2 million people and has one of the highest population densities in the world.
Just over 75% of Gaza’s population – some 1.7 million people – are registered refugees or descendants of refugees, according to the UN. More than 500,000 of them live in eight crowded camps located across the Strip.
Israel controls the air space over Gaza and its shoreline, and strictly controls the movement of people and goods.
What is Palestine?
The West Bank and Gaza, which are known as the Palestinian territories, as well as East Jerusalem and Israel all formed part of a land known as Palestine from Roman times until the mid-20th Century.
These were also the lands of Jewish kingdoms in the Bible, and are seen by many Jews as their ancient homeland.
Israel was declared a state in 1948, though the land is still referred to as Palestine by those who do not recognise Israel’s right to exist.
Palestinians also use the name Palestine as an umbrella term for the West Bank, Gaza and East Jerusalem.
The Palestinian president is Mahmoud Abbas, also known as Abu Mazen. He is based in the West Bank, which is under Israeli occupation.
He has been the leader of the Palestinian Authority (PA) since 2005, and represents the Fatah political party, a bitter rival of Hamas.
Source : BBC