Sustained US strikes could provide a major boost to pro-government forces in Anbar, where all of one city and chunks of another have been out of state control for more than nine months, along with other areas seized by militants since June.
– Vote on new government –
Western governments have come under mounting pressure to take strong action against IS, which controls a swathe of neighbouring Syria as well as significant territory north and west of Baghdad.
The jihadist group has carried out a spate of atrocities in areas it controls, some of which it has videotaped and paraded on the Internet, including the beheading of American journalists James Foley and Steven Sotloff.
If a new Iraqi government is not agreed on Monday, this will mean a return to the start of the contentious process, leaving the country rudderless at a critical time.
There have been repeated calls from the international community, including the United States, for a broad-based government to help confront the militants.
While this would ensure that all sides are represented, similar arrangements in the past have led to deadlock that has helped undermine government effectiveness.
