The Muslim pilgrims’ road to the holy city of Karbala became a highway of bullets and bombs for Shiites yesterday. Drive-by shootings and roadside and bus bombs killed or wounded 19 people, ratcheting up the sectarian tensions gripping Iraq.

Heliborne US and Iraqi troops pressed their sweep through a 100-square-mile section of central Iraq today in a bid to break up a centre of insurgent resistance, the US military said. No casualties were reported on either side.