Sunni militants extended their control over parts of northern and western Iraq on Wednesday as Iraqi government forces crumbled in disarray. The militants overran the city of Tikrit, seized facilities in the strategic oil refining town of Baiji, and threatened an important Shiite shrine in Samarra as they moved south toward Baghdad.
The remarkably rapid advance of the Sunni militants, who on Tuesday seized the northern city of Mosul as Iraqi forces fled or surrendered, reflects the spillover of the Sunni insurgency in Syria and the inability of Iraq’s Shiite-led government to pacify the country after American forces departed in 2011 following eight years of war and occupation.
By late Wednesday, witnesses in Samarra, 70 miles north of Baghdad, were reporting that the militants, many of them aligned with the radical Islamic State of Iraq and Syria or ISIS, were on the outskirts of the city. They said the militants demanded that forces loyal to the government leave the city or a sacred Shiite shrine there would be destroyed. Samarra is known for the shrine, the al-Askari Mosque, which was severely damaged in a 2006 bombing during the height of the American-led occupation. That event touched off sectarian mayhem between the country’s Sunni Arab minority and its Shiite majority.
Members of Shiite militias were on high alert in Baghdad, and many were reported headed north to Samarra, even though the central government declared a 10 p.m. curfew in the capital and surrounding towns. An influential Iraqi Shiite cleric, Moktada al-Sadr, called for the formation of a special force to defend religious sites in Iraq. The authorities in neighboring Iran, which is predominantly Shiite, canceled all visas and flights for pilgrims to Baghdad and intensified security on the Iran-Iraq border, Iran’s official Islamic Republic News Agency reported.
Insurgents also were holding 80 Turkish citizens seized in Mosul over the last two days, including the Turkish consul general, other diplomats and at least three children, the Turkish government said. Thirty-one of the Turkish hostages were truck drivers who had been transporting fuel to a power plant in Mosul.
The hostage-taking raised the possibility that Turkey, a NATO ally that borders both Syria and Iraq, would become directly entangled in the fast-moving crisis. Prime Minister Recep Tayyip Erdogan of Turkey was holding an emergency meeting with top security officials, and the Turkish foreign minister, Ahmet Davutoglu, cut short a trip to New York and was returning to Ankara. “No one should try to test the limits of Turkey’s strength,” Mr. Davutoglu said in a statement.
Turkey has long taken an interest in northern Iraq for economic reasons and because of the sizable and often restive Kurdish minority, which straddles the border and controls a region of Iraq east of Mosul.
Amid the collapse of the Iraqi army in Mosul, Tikrit and other northern cities, questions were raised about the possibility of a conspiracy in the military to deliberately surrender. Witnesses reported some remarkable scenes in Tikrit, where soldiers handed over their weapons and uniforms peacefully to militants who ordinarily would have been expected to kill government soldiers on the spot.
Prime Minister Nuri Kamal al-Maliki, a Shiite, suggested the possibility of disloyalty in the army when he exhorted Iraqi citizens on Tuesday to take up arms against the Sunni insurgents.
Residents of Baiji, a city of 200,000 about 110 miles south of Mosul, awoke Wednesday to find that government checkpoints had been abandoned and that insurgents, arriving in a column of 60 vehicles, were taking control of parts of the city without firing a shot, the security officials said. Peter Bouckaert, the emergency services director for Human Rights Watch, said in a post on Twitter that the militants had seized the Baiji power station, which supplies electricity to Baghdad, Kirkuk and Salahuddin Province
In Tikrit, the home town of Saddam Hussein, residents said the militants attacked in the afternoon from three directions: east, west and north. Residents said there were brief exchanges of gunfire, and then police officers and soldiers shed their uniforms, put on civilian clothing and fled through residential areas to avoid the militants, while others gave up their weapons and uniforms willingly.
On Wednesday, the insurgents claimed to have taken control of the entire province of Nineveh, Agence France-Presse reported, and there were reports of militants executing government soldiers in the Kirkuk region. Atheel al-Nujaifi, the governor of the province, criticized the Iraqi army commanders in Mosul, saying they had misled the government about the situation in the city.
Iraq’s foreign minister, Hoshyar Zebari, was quoted on Wednesday as saying his country’s Kurdish minority would “work together” with Baghdad’s forces to “flush out these foreign fighters.”
At a meeting of Arab and European foreign ministers in Athens, Mr. Zebari, himself a Kurd, called the insurgents’ strike “a serious, mortal threat,” adding: “The response has to be soon. There has to be a quick response to what has happened.”
Iraqi Kurds are concentrated in the autonomous region of Kurdistan, where security is maintained by a disciplined and fiercely loyal fighting force, the pesh merga, that has not yet become involved in the latest clashes.
In a further indication of the regional dimensions of the crisis, the government of President Bashar al-Assad in Syria, facing the same jihadist adversary in its civil war against a broader array of armed foes, expressed solidarity with the Iraqi authorities and armed forces, the official SANA news agency reported.
Word of the latest militant advance came as a United Nations agency reported that 500,000 people had fled Mosul — Iraq’s second-largest city, with a population of about 2 million — after the militants, spilling over the border from Syria, captured military bases, police stations, banks and provincial headquarters.
The International Organization for Migration, based in Geneva, said the civilians had mainly fled on foot, because the militants would not let them use vehicles and had taken control of the airport. Roughly the same number were displaced from Anbar Province in western Iraq as the militants gained ground there, the organization said.
On Tuesday the insurgents, reinforced with captured weaponry abandoned by the fleeing government forces, raised their black banner over streets in Mosul littered with the bodies of soldiers, police officers and civilians. The success of the militant attack was the most stunning development in a rapidly widening insurgency straddling the porous border of Iraq and Syria.
Mr. Maliki has ordered a state of emergency for the entire country and called on friendly governments for assistance in a quickly deteriorating situation. His weak central government is struggling to mount a defense, a problem made markedly more dangerous bythe defections of hundreds of trained soldiersand the loss of their vehicles, uniforms and weapons.
Security officials said the militant drive toward Baiji began late on Tuesday with brief clashes a few miles north of the town before the insurgents overran a security post, captured vehicles and set buildings on fire.
“They did not kill the soldiers or policemen who handed over their weapons, uniform and their military I.D.,” a security official in Tikrit said on Wednesday before the militants reached that city; he spoke on the condition of anonymity. “They just took these things and asked them to leave,” the official said.
The rising insurgency presented a new quandary for the Obama administration, which has faced sharp criticism for its recent swap of five Taliban officers for Sgt. Bowe Bergdahl and must now answer questions about the death of five Americans by friendly fire in Afghanistan on Monday night.
Critics have long contended that America’s withdrawal of troops from Iraq, without leaving even a token force, invited an insurgent revival.
The Obama administration, which has expressed alarm about the events in Iraq and offered the government unspecified support, sharpened a longstanding travel warning to Americans on Wednesday about the risks of visiting the country. “Travel within Iraq remains dangerous given the security situation,” the State Department said in an advisory. It said American citizens remained “at high risk for kidnapping and terrorist violence.”