South Korea said Monday it was "closely watching" for any signs of an imminent North Korean missile test after Pyongyang reportedly issued a no-sail zone off its east coast.

The South's Yonhap news agency had quoted a government source on Sunday as saying the North had imposed the no-navigation zone off the coastal city of Wonsan from November 11 to December 7.

The men vying to be Argentina's next president, conservative mayor Mauricio Macri and center-left governor Daniel Scioli, squared off Sunday in their lone debate before the November 22 run-off election.

In a feisty encounter, Scioli sought to claw back the front-runner status he has lost since the October 25 first-round race, but neither candidate landed a knock-out punch and both appeared more interested in taking pot shots than answering moderators' questions.

Britain is to recruit an extra 1,900 security and intelligence staff to counter the threat of terrorist violence following the deadly Paris attacks, British media reported on Monday.

The move would be "the biggest increase in British security spending since the 7/7 bombings in London" that killed dozens in 2005 and will be announced by Prime Minister David Cameron later on Monday, according to the Guardian.

Paraguay's ruling conservative party lost the mayor's office in the capital Asuncion on Sunday in a surprise midterm setback for President Horacio Cartes.

Popular TV presenter Mario Ferreiro defeated incumbent Arnaldo Samaniego of the president's Colorado party, 51.2 percent to 40.4 percent, according to official results with nearly all ballots counted.

The second Democratic presidential debate drew 8.55 million viewers, host network CBS said Sunday, about half as many as the party's debut debate in the campaign cycle last month.

Saturday's primetime debate in Des Moines, Iowa came a day after the terror attacks on Paris and saw a heavy focus on what frontrunner Hillary Clinton, Vermont Senator Bernie Sanders and former Maryland governor Martin O'Malley would do about the Islamic State extremist group.

"Why are the people crying, Mummy?" a little girl out for a Sunday afternoon cycle with her parents asked, as she passed the crowds gathered on the street corner where the killing began in central Paris.

"They are very sad," her mother said as she tried to navigate the groups standing silently and awkwardly facing the Petit Cambodge restaurant and the Carillon cafe, trying not to look at the patches of bloodstained sand on the pavement where the 14 people who died there fell.

Firecrackers and exploding light bulbs and heaters triggered scenes of panic in Paris on Sunday, as rumors of fresh shootings sent people diving for cover and calling for police.

"We were just singing along with a group of young people when everyone started to run, so we ran too," said a 23-year-old who gave her name only as Laurine.

U.S. President Barack Obama arrives in the Philippines Tuesday with his much-vaunted "pivot to Asia" again overshadowed by events in Europe, the Middle East and politics at home.

Obama will touch down in Manila with the world's focus on the murderous attacks in Paris claimed by the Islamic State group and soul searching about how to counter it in Syria and Iraq.

Turkish authorities foiled a plot to stage a "major" attack in Istanbul on the same day as the deadly gun and suicide attacks in Paris, a senior official said on Sunday.

Police on Friday detained five people in Istanbul, the source told AFP, including a suspected close associate of the notorious Islamic State (IS) group militant known as "Jihadi John" who Washington believes was likely killed in a recent drone strike in Syria.

The defense ministers of France and the United States agreed Sunday on "concrete steps" to intensify cooperation against the Islamic State group, the Pentagon said.

U.S. Defense Secretary Ashton Carter and French Defense Minister Jean-Yves le Drian discussed by telephone the actions they are taking in response to Friday's terrorist attacks in Paris that killed at least 129 people.