President Bashar al-Assad is determined to retake Syria's second city Aleppo to deal a decisive blow to the rebels ahead of a possible change in US foreign policy, analysts say. 

Assad's regime has in recent months been pressing a series of offensives to seize control of the devastated city's east, which has been in rebel hands since 2012.

From Dwight Eisenhower, who broke U.S. diplomatic relations with Cuba, to Barack Obama, who decided to normalize them, 11 U.S. presidents faced off with Cuban revolutionary leader Fidel Castro, who died late Friday.

-- Dwight Eisenhower (Republican, 1953-1961): Provided arms to dictator Fulgencio Batista, who was battling Castro's rebels. Prepared the invasion of the Bay of Pigs and broke off diplomatic ties with Cuba in January 1961.

After surviving more than 600 assassination attempts, defying 11 U.S. presidents and shaping half a century of history, Fidel Castro has died at age 90.

Here are six snapshots of this magnetic, polarizing giant of the 20th century, who beat the odds to hang on well into the 21st.

With the death of Fidel Castro, the United States has lost its last great Cold War enemy, a leader who long ago passed the baton to his brother and sat on the sidelines during his country's historic rapprochement with its old foe.

The loss of the firebrand who flouted America's superpower status under 11 US presidents comes as Washington is poised to undergo a major transition from the administration of Barack Obama to that of the brash Republican billionaire Donald Trump.

One year after the crisis that plunged relations between Russia and Turkey to a post-Cold War low, Vladimir Putin and Recep Tayyip Erdogan have overseen a spectacular revival in ties at a time when both are facing new tensions with the West.

The shooting down of a Russian military jet over the Syrian border by the Turkish air force on November 24 2015 was the culmination of months of tensions over the civil war, prompting Moscow to impose retaliatory sanctions on Ankara. 

The Syrian army's advances against rebels in east Aleppo have sparked international concern, but the world appears powerless to prevent the symbolic city from being recaptured by the government.

Iraqi civilians who escaped from the Islamic State group stronghold of Mosul said jihadists forced them from their villages and drove them "like sheep" to use as human shields.

Bus driver Adem Alomerovic was returning home to southern Serbia after undergoing medical tests in Belgrade when he was hauled off a train by members of a notorious militia as it crossed through Bosnian territory.

Iraqi forces have broken into jihadist-held Mosul and recaptured neighborhoods inside the city, but a month into their offensive, there are still weeks or more of potentially heavy fighting ahead.

Turkey is heading to a referendum on granting President Recep Tayyip Erdogan new powers as early as next spring, ratcheting up tensions amid a crackdown on dissent and pro-Kurdish politicians, analysts say. 

The courts have arrested over 35,000 people under a state of emergency imposed in the wake of the failed July 15 coup aimed at unseating Erdogan whose defeat the authorities see as a triumph of Turkish democracy.