SAMARRA, Iraq (Reuters) - In northern Iraq, residents fearful of al Qaeda militants hurry home before the sun sets. Cities are virtual ghost towns after dark.
The U.S. military and Iraqi officials have hailed vastly better security in Baghdad, western Anbar province and areas south of the capital, which has allowed people to venture out at night to shop at markets and eat at restaurants.
But in the cities of Samarra, Baquba and Mosul, the militants still sow fear.
"When I don't see al Qaeda wandering around Samarra, pointing weapons in the faces of Iraqis and killing and kidnapping, then I will say security has improved," said grocer Nihad Hameed in the city, 100 km (62 miles) north of Baghdad.
"We come back home at 7 p.m. like chickens. No one can move after that."
U.S. and Iraqi security forces as well as Sunni Arab tribal units have expelled Sunni Islamist al Qaeda from its strongholds in Anbar and the roads around Baghdad, which the militants used as a springboard to launch attacks on the capital.
Many of the militants have since regrouped in northern provinces where U.S. forces were less concentrated and Sunni Arab tribal units had only recently been established.
U.S. and Iraqi troops have launched offensives against al Qaeda this year in northern provinces such as Diyala, Salahuddin and Nineveh. But the campaign is expected to take time.
"Everything in Baquba stops the minute it gets dark," Nada Amaar, a doctor, said from the capital of ethnically and religiously mixed Diyala province.
Ali Muhsin Dawud, 45, a car dealer in Baquba, said he was thinking of moving to another city.
Militant violence in northern provinces comprises 60 percent of all attacks in Iraq, with an average of 66 incidents reported a day during the past year, said Captain Stephen Bomar, a spokesman for the U.S. military in the north.
Attacks overall in the north have slowed in recent months, falling 42 percent since June, compared to a 60 percent drop for the whole of Iraq.
"There is not a safe haven left for these insurgents anywhere, and an unorganized movement to the north is believed to be a last effort to randomly hurt the Iraqi people," said Bomar, adding safety was getting better every day in the north.
In Nineveh, however, attacks have actually risen -- the only part of Iraq where this has happened -- the U.S. military commander in Iraq, General David Petraeus, said last week.
Iraqi military and provincial officials in northern provinces acknowledge the concerns of residents. Some have those fears themselves, although they say security is better.
"I cannot walk by myself in Tikrit. I might be killed or kidnapped," said Brigadier-General Muaid al-Tikriti, the Iraqi army chief in Saddam Hussein's home town in Salahuddin province.
A key factor in stabilizing northern provinces will be the Sunni Arab tribal units, which in other parts of Iraq have rebelled against al Qaeda because of its indiscriminate attacks on civilians and harsh interpretation of Islam.
Violence has also fallen in Baghdad and mainly Shi'ite southern Iraq because of a ceasefire by the feared Mehdi Army militia of Shi'ite cleric Moqtada al-Sadr.
Called "concerned local citizens" by the U.S. military, the Sunni Arab tribal units man checkpoints and provide tips on al Qaeda hideouts.
But strains have emerged, especially in Baquba where the units, some comprised of former Sunni Arab insurgents who opposed the Shi'ite-led government, have threatened to quit because of disputes with the city's police chief, a Shi'ite.
Ibrahim al-Bajilan, head of the Diyala provincial council, predicted attacks would double if the tribal units walked away.
The other key trouble spot in the north is Mosul, a city of 1.6 million people that is the capital of Nineveh and regarded as al Qaeda's last urban stronghold.
Prime Minister Nuri al-Maliki has promised a final, "decisive" battle against al Qaeda in Mosul. U.S. commanders caution the operation will take months.
Fear and rumor pervades Mosul, home to mainly Sunni Arabs but also sizeable communities of Shi'ites and Kurds.
Many people distrust not only al Qaeda, but also the Shi'ite-dominated Iraqi security forces. They fear curfews and a mass roundup of suspected militants.
The commander of Nineveh military operations, Major-General Riyadh Tawfiq, promised that arrests would be based on specific intelligence and that no curfew would be imposed.
Locals are taking no chances. Some residents have stocked up on food in preparation for a period of extended fighting.
"I expect the local government will impose a curfew and I'm shopping in anticipation of that," said goldsmith Naseer Hatam, hurrying home with a box of cooking oil and tomato paste.
Additional reporting by Aseel Kami in Baghdad; Writing by Mohammed Abbas; editing by Dean Yates and Charles Dick