For the second US presidential debate, Sunday night in St Louis, the pressure is squarely on Donald Trump, who needs a moment of political magic to reverse his slide in polls barely four weeks from Election Day.

- Donald Trump -Even though the Republican candidate trails Hillary Clinton in the polls, he wasted opportunities to regain the advantage over his Democratic rival in their September 26 showdown. 

The Nobel Peace Prize, awarded Friday to Colombian President Juan Manuel Santos despite a popular rejection of the terms of his deal with FARC rebels, has highlighted fragile peace processes several times in the past.

Nearly a month after the September 11 attacks that killed 3,000 people, the US launched its first major salvo in the "war on terror" by invading Afghanistan -- where, 15 years on, thousands continue to die each year.

Palestinian President Mahmoud Abbas received a clean bill of health after undergoing an emergency heart procedure on Thursday. But his brief hospitalization drew attention to the lack of a clear successor to the aging leader and the ongoing rift between rival governments in the West Bank and Gaza Strip.

Abbas, leader of the Fatah Party, was elected president of the Palestinian Authority in 2005 in what was supposed to be a four-year term. One year later, the rival Hamas militant group defeated Fatah in parliamentary elections and violently seized control of Gaza in 2007. Abbas has remained in control of parts of the West Bank ever since, while no national elections have been held.

With Barack Obama's presidency coming to a close and US policy for Syria at an impasse, Vladimir Putin's Russia has stepped up efforts to secure its ally Bashar al-Assad in power.

US officials fear the Kremlin is racing to consolidate its gains in Syria before a new, possibly tougher administration takes charge, but there is little sign of a clear new policy emerging.

The Colombian people's shock rejection of a peace deal between Bogota and the communist FARC rebels has all but annihilated the former enemies' chances of securing a Nobel peace award, experts said Monday. 

Colombian President Juan Manuel Santos and FARC chief Rodrigo Londono, alias Timoleon "Timochenko" Jimenez, had until now appeared to be serious contenders for the prestigious award after signing a deal on September 26 to end 52 years of civil war. 

Saudi Arabia could reduce valuable security and intelligence cooperation with longstanding ally Washington after a Congressional "stab in the back" allowing 9/11 victims to sue the kingdom, experts warn.

Cutting such cooperation is among the options available to Riyadh after Congress voted overwhelmingly on Wednesday to override President Barack Obama's veto of the Justice Against Sponsors of Terrorism Act (JASTA).

Russia one year ago carried out its first air strikes in support of Syrian President Bashar al-Assad's forces, in a major turning point in a multi-sided civil war.

Former Israeli president Shimon Peres, who died on Wednesday aged 93, was the last survivor of the three men awarded the Nobel Peace Prize for the Oslo accords.

The agreements, signed in the early 1990s, were meant to create a "lasting and comprehensive peace settlement" between Israelis and Palestinians and were hailed across the world. 

Democrat Hillary Clinton and her Republican White House rival Donald Trump went head-to-head on Monday night in a prime-time duel in front of tens of millions of American voters.

Here is a selection of key quotes from the first of three debates leading up to the November 8 election: