Afghanistan: Insurgents in northern Iraq seize key cities, advance toward Baghdad --- IRBIL, Iraq — Insurgents inspired by al-Qaeda rapidly pressed towards Baghdad on Wednesday, confronting little resistance from Iraq’s collapsing security forces and expanding an arc of control that now includes a wide swath of the country. -- By nightfall, the militants had reached the flashpoint city of Samarra, just 70 miles outside Baghdad, after having first seized Tikrit, Saddam Hussein’s hometown, and other cities while pressing southward from Mosul. -- The stunning speed with which the rout has unfolded in northern Iraq has raised deep doubts about the capacity of U.S. -trained Iraqi security forces, and it has also kindled fears about the government’s grip on the capital itself. -- In a country already fraught with sectarian tension, with parts of western Iraq already in Sunni militant hands, the latest gains by insurgents from the Islamic State of Iraq and Syria prompted ominous cries of alarm from leaders of Iraq’s Shiite Muslim majority. -- It appeared that the militants were facing more robust resistance as they moved south, where Iraq’s Shiites have a stronger presence. But several experts said that it would be wrong to assume that heavily fortified Baghdad, with its large Shiite population and concentration of elite forces, could easily fend off an ISIS attack. -- Baghdad is “definitely vulnerable,” said Raoul Alcala, a former U.S. adviser to Iraq’s national security council who has spent most of the past decade in Iraq. “There are more troops in Baghdad, but it doesn’t mean it isn’t porous.’’ -- A separate analysis posted on the Web site of the Washington-based Institute for the Study of War said insurgents advancing from the north could link up with counterparts on the city’s perimeter to pose a real threat to the capital. -- For his part, the Iraqi prime minister, Nouri al-Maliki, insisted for a second straight day that security forces were capable of reversing the militants’ gains. In a televised address to the nation, he pledged that Mosul, the largest city in northern Iraq, which fell to insurgents overnight Monday, would soon be back in government hands. -- “This is just the latest round of fighting against ISIS, and it won’t be the last,” he said. --- In Washington, the State Department said the United States is “expediting” the delivery of critical weaponry to the Maliki government but gave few details. “You can expect that we will provide additional assistance to the Iraqi government to combat the threat,” said Jen Psaki, the State Department spokeswoman. -- Among those caught up in the fighting were dozens of Turkish citizens, including some diplomats, who were being detained by militants during attacks in Mosul that included a strike on the Turkish consulate there. -- The conflict in the city, which began Monday evening, has sent hundreds of thousands of civilians fleeing, many into the safety of the semi-autonomous Kurdish region of northern Iraq. Civilians fleeing from Mosul gave an insight into why ISIS has been able to gain such a strong foothold in the Sunni-majority city, where anti-government sentiment is high.