Iraqi forces worry about future major attack by armed groups

Al-Qaida affiliates still viewed as capable threat to country's stability

BAGHDAD - Improved security in Baghdad and a lull in assassinations in the last three weeks may merely signal that armed groups are preparing a major attack in the Iraqi capital, a senior official said.

Violence has dropped sharply overall since the height of Iraq's sectarian conflict in 2006-2007, but both Shiite and Sunni Muslim groups remain responsible for killings, bombings and attacks that happen almost every day.