Insurgents gunned down 19 Iraqi police and soldiers yesterday in clashes around Baquba, as US and Iraqi forces intensified offensive operations in a rebel-infested city that the Americans subdued last year — only to have the Iraqis lose control. Eight policemen died in a pair of shootouts in Baquba, 55 kilometers (35 miles) northeast of Baghdad, officials said. Six policemen and two soldiers were killed in another gunbattle in the Baquba suburb, officials said. Three Iraqi soldiers also died yesterday when their convoy was attacked by gunmen near Adhaim, 50 kilometers (30 miles) north of Baquba, police said. To the north, fighting raged for a second day yesterday in the outskirts of Tal Afar, an ethnically mixed insurgent stronghold 420 kilometers (260 miles) northwest of Baghdad. US and Iraqi officials urged civilians to leave affected areas of the city, a sign that the Americans are preparing a major assault. US forces crushed insurgents in Tal Afar last fall, leaving only about 500 American soldiers behind and handing control over to the Iraqis. But Iraqi authorities lost control of the city, and insurgent ranks swelled. That forced the US command to shift the 3rd Armored Cavalry Regiment from the Baghdad area to Tal Afar to restore control. Yesterday, US and Iraqi forces were firing at insurgents on the western side of the city, Iraqi officials said.