Rebels in South Sudan have denied shooting down a UN helicopter, which crashed on Tuesday, killing 3 and injuring one of those on board.

The rebel SPLM dismissed the claims made by the South Sudanese army as government propaganda.

"The SPLM/SPLA [in Opposition] would like to take this opportunity to refute these malicious allegations levelled by the propaganda machine of the Government of the Republic of South Sudan (GRSS)," said the statement, which bore the signature of Mabior Garang de Mabior, the chairperson of the committee for information and public relations.

"The area in which the plane was reportedly shot down is government-held territory, if indeed the aircraft was shot down. It is unfortunate that the GRSS propaganda machine is trying to capitalise on this unfortunate event to score political points,"

According to the Sudan Tribune, rebel brigadier-general Lul Ruai Koang pledged to assist any investigations.

The UN has accused the Syrian government and rebels opposed to it of committing war crimes in Syria.

A report released by the Independent International Commission of Inquiry on the Syrian Arab Republic details abuses by Islamic State and other rebel groups fighting Bashar al-Assad’s regime.

The government is thought to have conducted chemical attacks eight times this year alone and used barrel bombs on civilian areas.

"In some instances, there is clear evidence that civilian gatherings were deliberately targeted" by government forces, the investigators said.

"In government prisons, detainees were subjected to horrific torture and sexual assault."

A long-term truce has been agreed between Israelis and Palestinians, after intense negotiations, brokered by Egypt.

Palestinian and Egyptian officials announced the end to 7-weeks of fighting, which killed over 2,200 people, mostly Palestinian civilians.

Hamas spokesperson Sami Abu Zuhri said in a statement, “An agreement has been reached between the two sides and we are awaiting the announcement from Cairo to determine the zero hour for implementation.”

Ismail Haniya, the former Hamas prime minister in Gaza, told Al Aqsa television that “we are at the doors of political understandings that will crown our people’s steadfastness and the performance of our armed resistance.”

President Barack Obama has approved surveillance flights over Syria to gain information on Islamic State militants.

The flights, which are reported to have commenced on Tuesday, are widely seen as a precursor for expanding the range of US airstrikes on IS positions in Iraq into Syria, according to The Guardian.

US officials ruled out cooperating with the Syrian government on fighting IS.

Nearly 500 Nigerian soldiers have fled into Cameroon after severe clashes with Boko Haram fighters, according to Cameroon’s army.

Spokesman Lt Col Didier Badjek told the BBC that the soldiers have been disarmed and are being accommodated in schools in Maroua, around 80km from the Nigerian border.

Thousands of civilians are also thought to have crossed the border into Cameroon. Clashes are reported to be ongoing in the border town of Gamboru Ngala.

Ukrainian troops have engaged in clashes with Russian troops which crossed the border in the southeast of the country.

Ukrainian military spokesperson Andriy Lysenko said Russian military vehicles with the insignia of the self-proclaimed Donetsk People’s Republic “violated the state border of Ukraine” in the southern part of Donetsk region.

Lysenko said at least 10 tanks, two armored vehicles and two trucks from Russia crossed into the country on Monday soon after which they engaged in clashes with a Ukrainian military border unit.

The Syrian government says it will help the US fight Islamic State militants, who have seized huge swathes of land across Syria and Iraq.

Foreign Minister Walid Muallem said Syria was "the centre of the international coalition to fight Islamic State", adding that the US must coordinate with Syria before launching attacks in its territory.

"Anything outside this is considered aggression," he said.