More than five million people have fled Syria since the conflict began, and half of them are children.

The Syrian refugee crisis remains one of the largest humanitarian crises since the end of World War II. The number of refugees who have fled the country now exceeds five million, including more than 2.4 million children, and millions more have been displaced internally, according to the United Nations.

Syrians have poured across their borders since anti-government protests in 2011 spiralled into a full-blown war between rebels, government troops and foreign backers.

The first three months of 2017 saw more than 250,000 additional Syrians register as refugees, bringing the total to 5.1 million, according to the UN's refugee agency, UNHCR.

"It's not about the number, it's about the people," UNHCR spokesman Babar Baloch said, noting that the conflict has now lasted longer than World War II. "We're trying to look for understanding, solidarity and humanity."

Turkey continues to host the highest number of displaced Syrians, at nearly three million, with an increase of 47,000 since February, Baloch said.

When is a person considered a refugee?

Refugees are persons forced to leave their homes and countries because their lives and freedoms are in danger.

The 1951 Geneva Convention Relating to the Status of Refugees describes a refugee as any person who, "owing to well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality and is unable or, owing to such fear, is unwilling to avail himself of the protection of that country".

But this definition has been broadened to cover persons who are forced to leave their countries because of widespread violence, war and foreign occupation that has put their lives at risk in their home countries.

The reason for leaving one's country is considered as the main factor in distinguishing refugees from migrants.

How and when did the Syrian refugee crisis start?

The flow of Syrian refugees to neighbouring countries started during the onset of the civil war in 2011.

The Arab Spring in Tunisia, Egypt and other Arab countries inspired protests in Syria, prompting a crackdown by the Syrian army. As Syria descended into a civil war, it became divided into a complex battle between the government, rebel groups and foreign backers.

By May 2011, the number of refugees crossing the Turkish border was estimated at just 300.

What countries have taken in Syrian refugees, and which country has the most?

According to Amnesty International, Syrian refugees have sought shelter in five countries throughout the Middle East, including Turkey, Lebanon, Jordan , Iraq and Egypt.

Turkey is the largest host country of registered refugees, with nearly three million.

None of the six states that form the Gulf Cooperation Council - Saudi Arabia, Oman, the United Arab Emirates, Kuwait, Bahrain and Qatar - has signed the UN convention on refugees, which has governed international law on asylum since World War II.

However, the Gulf states say they have taken in hundreds of thousands of Syrians since the civil war began - just not as refugees.

Are all the Syrian refugees in Europe? Not really.



Here is a breakdown of where they are right now https://t.co/LsMn3hIRs3 pic.twitter.com/VZtPX9erBw — Al Jazeera English (@AJEnglish) May 25, 2017

Can refugees become citizens?

In 2016, Turkish President Recep Tayyip Erdogan said that Syrian refugees living in Turkey could eventually be granted citizenship, but he gave no details on eligibility criteria or how long the process would take.

In Jordan, more than 26,000 Syrians have obtained work permits, but refugees do not automatically acquire rights to residency.

More than one million Syrian refugees have made Lebanon their temporary home, but last year, President Michel Aoun vowed to send them back to their home country.

Egypt also became a major destination for Syrian refugees, but many have since fled their adopted homeland, in part because of a rising tide of anti-Syrian sentiment that took hold during the unrest following the toppling of the country's first democratically elected president, Mohamed Morsi, in 2013.

Source: Al Jazeera