Egypt launched airstrikes against Islamic State militant group locations in Libya's city of Derna early on Monday, hours after the group released a video of it beheading 21 Egyptian Coptic Christian hostages.
For decades, Libya has been a major destination for Egyptian migrant workers due to its once booming oil economy, geographical proximity and open borders.
Until April 2011, Egyptians were allowed to enter and reside in Libya without a visa.
No official number exists for Egyptian workers in Libya, Egypt's manpower minister Nahed El-Ashri told the press on Friday, because large numbers travel illegally into the oil-rich North African country. She however estimated the number to stand between 800,000 and 900,000.
Other unofficial estimates bump up the number to 1.5 million Egyptian workers.
The International Organisation for Migration estimated that 330,000 to 1.5 million Egyptians worked in Libya until Muammar Gaddafi was toppled in 2011, sending between 19.5 and 33 millions of dollars back to Egypt in remittances.
Since the 2011 toppling of dictator Muammar Ghaddafi, rival militias have been fighting a weak central government across the country.
Instability in Libya has prompted many Egyptian workers to return to Egypt, others have remained.
Last August, the Egyptian foreign ministry cautioned Egyptians against travelling to Libya and advised expatriates there to avoid clashes.
In December, Egypt renewed its warning to citizens living in Libya.
Today, an internationally-recognised government headed by Abdallah El-Thinni and parliament is based in the eastern city of Tobruk, and has little to no control in the capital Tripoli or other cities.
A rival Islamist government led by Omar El-Hassi controls Tripoli.
Ahram Online has compiled a list of some of the main events in which Egyptians, both Muslims and Christians, were abducted by armed Libyan groups and how the authorities reacted over time.
18 October 2013: Dozens of Egyptian truck drivers were held by a Libyan armed group in the city of Ajdabiya to press for the release of Libyans detained in Egypt. It was not clear how many Egyptians were seized but some estimates took it up to 150 people. They were freed two days later.
25 January 2014: Gunmen kidnapped four Egyptian diplomats, including the cultural attaché, from their homes in the Libyan capital Tripoli. A fifth diplomat was kidnapped the day earlier. The kidnappers asked for the release of Libyan militia leader Shabaan Hadia. The kidnaps prompted Cairo to evacuate its embassy in Tripoli and its consulate in Benghazi. The next day, the five diplomats were released. The day after that, the Egyptian authorities released Libyan militia leader Shabaan Hadia, following the release of the diplomats.
4 February 2014: Armed Libyan groups stopped at least 300 Egyptian and Libyan trucks, with their drivers, to press the Libyan government to answer their demands.
Also in February, The bodies of seven Egyptian Coptic Christians who had been shot were found near Benghazi.
14 March 2014: Nearly 70 Egyptian workers were abducted by armed Libyan militias.
4 April 2014: Armed Libyans detained 50 Egyptian trucks heading from Libya to Egypt, along with their drivers, in protest against the Egyptian judiciary sentencing Libyan smuggler Salama Mohamed Salama to life in prison.
15 May 2014: Around 250 Egyptian truck drivers were held, reportedly by Libyan militiamen, in the north-eastern city of Ajdabiya by security personnel demanding late wages. The drivers were released two days later after the security personnel were promised they would be paid.
25 August 2014: Four Coptic Christians were abducted while attempting to head back to Egypt near Sirte. Armed men stopped the vehicle in which the Copts were riding, along with three Egyptian Muslims, and asked for their passports. They took the four Copts hostage, and left the rest, reports said.
20 September 2014: Over 30 Egyptian trucks, and their estimated 70 drivers, were detained by a Libyan militia demanding the release of three Libyans held by Egyptian authorities on charges of drugs and weapons smuggling. They hostages were released 10 days later.
9 October 2014: Egyptian and Libyan top officials agreed that Egypt would train Libya's security forces to help fight "terrorism".
15 October 2014: A report by AP quoting unnamed security officials said that Egyptian warplanes attacked Islamists and their posts in the eastern city of Benghazi. Both the Egyptian and the Libyan forces denied that Egypt conducted any attacks. Egyptian President Abdel-Fattah El-Sisi on several occasions reiterated that the army did not carry out operations outside of the Egyptian territory.
31 October 2014: Libyan militants in the eastern Libyan city of Derna, close to the Egyptian borders, swore allegiance to the Islamic State (IS) group, the first city to join the group from outside Syria and Iraq, where IS established strong presence.
23 December 2014: Armed men abducted a teenage Egyptian Coptic Christian girl after murdering her parents in Sirte. She was later found dead.
29 December 2014: Seven Egyptian Coptic Christian men were kidnapped from a vehicle near the Libyan city of Sirte, 500 kilometres east of Tripoli, which falls under the control of Islamist militias, including the Al-Qaida-linked Ansar Al-Sharia group.
3 January 2015: Islamist militants stormed a residential complex in Libya's city of Sirte and abducted 13 Coptic Christian Egyptians.
14 February 2015: 21 Egyptian fishermen were held in Libya's coastal city of Misrata, according to a fisherman community leader in Egypt's Kafr El-Sheikh governorate, from where the fishermen hail. Their fate is still not clear.
15 February 2015: IS released a graphic video showing the beheading of the Egyptian hostages on a beach they said was in Libya's Tripoli. The 21 Coptic Christian workers are mostly from impoverished villages in the southern city of Minya.
16 February 2015: The Egyptian army announced it has conducted air strikes against Islamic State militants' targets in Libya, including training camps and arms depots.