Iraq Fifteen people were killed and scores wounded in a car bomb attack on a Shiite mosque in Baghdad as they celebrated a major Muslim holiday, after Al-Qaeda's frontman in Iraq threatened to fan the flames of civil war. US US President George W. Bush began his second term in office at the White House after vowing in a tough inauguration speech to overthrow tyranny and spread freedom and democracy to the "darkest corners" of the world. Mideast Palestinian security forces took up positions across the northern Gaza Strip with orders to prevent attacks by militants, winning plaudits for new leader Mahmud Abbas from Israel. Space The European robot lab Huygens found liquid methane on the Saturn satellite Titan, a chemical that seems to have shaped the moon's peculiar landscape and weather system, scientists said in their first detailed assessment of the probe's mission. Iran Russia and France said that there was no alternative to holding negotiations with Iran to force the Islamic regime to abandon nuclear weapons and that Washington appeared to agree with this view. Ireland An Irish appeal court annulled the only criminal conviction over the 1998 Omagh bombing, the single worst terrorist attack in Northern Ireland's history, ordering a retrial. Asia The Muslim Eid al-Adha festival was a sombre, subdued affair in deeply religious Aceh with Indonesian President Susilo Bambang Yudhoyono leading tsunami survivors in prayer and mourning. Iraq Kidnappers who have threatened to kill eight Chinese nationals abducted in Iraq have said they would show "mercy" toward them if Beijing banned its citizens from going to the war-torn country, Al-Arabiya TV said. Denmark A female Danish military intelligence officer and four male military police sergeants will face a court martial for allegedly abusing Iraqi prisoners last year, the defense ministry said. HongKong Some 15,000 Hong Kong residents gathered to mourn purged Chinese reformer Zhao Ziyang, who died Monday, at a candlelit vigil in what was the only memorial held on Chinese soil.