Hospital sources in the western Iraqi city of Falluja say that at least 15 people were killed in a joint US-Iraqi attack. According to witnesses, US artillery bombarded several districts in the city, before US warplanes opened fire.

This follows a weekend in Iraq that saw a sharp escalation of violence and killings. Some estimates put the number of dead at more than 100. Sunday was marked by guns battles, car bombs and attacks from US helicopter gunships. The Iraqi Health Ministry said the worst fate was suffered in the Iraqi capital, where at least 37 people were killed and in Tal Afar near the Syrian border where some 51 people are confirmed dead. As has been the case from the beginning, Iraqi civilians have paid the heaviest price.

In one of the heaviest barrages in Baghdad in recent months, the capital suffered at least seven car bombs, and insurgents fired a dozen mortar bombs or rockets around the so-called Green Zone compound housing Iraq’s interim government and the US embassy. South of Baghdad, three Polish soldiers were killed and three wounded when they were attacked near Hilla.

In the western city of Ramadi, US tanks and helicopters fired on a residential district, killing 10 Iraqis, including women and children. The widespread violence comes as US forces began a nationwide offensive the Pentagon has said is aimed at securing the country for January’s planned elections. The unelected Iraqi Prime Minister Iyad Allawi told British newspapers over the weekend that some of the worst hit towns may not be able to vote in the elections but that they would take place without those voters.