A rebel delegation flew out of the Yemeni capital Tuesday accompanied by a U.N. peace envoy, heading for high-stakes talks in Sweden with the government aimed at ending the country's devastating war.

The humanitarian crisis in Yemen, already the world's worst, will deteriorate in 2019, the UN said Tuesday, warning that the number of people needing food aid is set to jump by four million. 

Yemen's Saudi-backed government and the Huthi rebels have agreed to exchange hundreds of prisoners ahead of planned peace talks in Sweden, sources said Tuesday.

The deal covers between 1,500 and 2,000 members of the pro-government forces and between 1,000 and 1,500 rebels, government official Hadi Haig told AFP.

CIA director Gina Haspel has agreed to brief a "small group" of US lawmakers about the murder of Saudi journalist Jamal Khashoggi, the chair of the Senate foreign relations committee said Monday.

Proposed UN-led talks in Sweden mark a "critical opportunity" to bring peace to war-torn Yemen after four years of conflict, a top Emirati official said Tuesday.

Algeria's President Abdelaziz Bouteflika called off a meeting with visiting Saudi Crown Prince Mohammed bin Salman on Monday because of ill health, the national news agency APS reported.

A Saudi dissident has filed a lawsuit against an Israeli surveillance company, claiming its sophisticated spyware targeted him and helped lead to the killing of his friend, Saudi journalist Jamal Khashoggi.

The suit, filed in a Tel Aviv court on Sunday, follows others previously filed against the company. But because of the dissident's ties to Khashoggi and his high-profile killing Oct. 2 at the Saudi Consulate in Istanbul, it is likely to shine a greater spotlight on the Israeli company and the Israeli government, which licenses the export of the surveillance technology.

A military court in the Hamas-run Gaza Strip on Monday sentenced six people, including a woman, to death by hanging for "collaborating" with Israel, authorities said.

Egypt's President Abdel Fattah al-Sisi inaugurated Monday the first arms fair organised in Cairo, where hundreds of companies are exhibiting, state TV footage showed.

Egypt refuses to accuse police officers suspected by Italy of involvement in the grisly murder of an Italian student because of a lack of evidence, the authorities said.

Giulio Regeni, a 28-year-old doctoral researcher at Britain's Cambridge University, disappeared in Cairo in January 2016.