Fighting has been continuing in Iraq's western Anbar Province, where security forces and their Sunni tribal allies are battling an offensive by Al-Qaeda-linked militants.
The AFP news agency said security forces backed by tanks were in action against militants on January 9 in the Albubali region, between Ramadi and Fallujah.
Battles were reported on January 8 in both cities, parts of which were seized early in the new year by militants linked to the Islamic State of Iraq and Levant group, an Al-Qaeda affiliate.
Casualty tolls from the latest violence weren't immediately known. But the violence since the beginning of the year is believed to have left at least scores of people dead or injured.
Human Rights Watch has accused both government forces and militants of committing abuses, saying, "Apparently unlawful methods of fighting by all sides have caused civilian casualties and severe property damage."
The New York-based group said there was evidence that government forces had used indiscriminate mortar fire in civilian neighborhoods, and that militants had deployed in, and attacked from, populated areas.
Aid agencies have warned that the fighting has blocked access by some residents to supplies of food, water, and fuel. Thousands of families are reported to have fled their homes in the past week.
U.S. Sends Weapons, Urges Reconciliation
The United States said Vice President Joe Biden had urged Prime Minister Nuri al-Maliki to pursue political reconciliation between Iraq's sharply divided Shi'ite and Sunni communities by reaching out to local, tribal, and national leaders.
It was the second phone call between Biden and Maliki this week.
The United States has already announced it is speeding up the delivery of military equipment to Iraqi forces to help in the fight. Officials said the U.S. aid will include air-to-surface Hellfire missiles, as well as drones for reconnaissance.
However, Washington has ruled out dispatching troops. U.S. combat troops left Iraq at the end of 2011, and officials say there are no plans for them to return.
Analysts say the situation marks one of the most serious challenges to Maliki in his eight years in power as head of the Shi'ite-led government.
The violence has come just months before Iraq is scheduled to hold parliamentary elections, at the end of April.
So far, Maliki has held off unleashing the Iraqi Army against the militants inside Ramadi and Fallujah, which is located just west of Baghdad.
The prime minister has said he is prepared to give Sunni tribal chiefs an opportunity to oust the militants on their own and regain control of their communities.
Analysts say tensions between Iraq's majority Shi'a and the minority Sunnis could be further strained if the army moves into the cities. Relations are already tense following years of complaints from Sunnis that they are being marginalized by Maliki's government.
The militant offensive marks the first time in around a decade that Sunni insurgents have seized and held territory in major cities in Anbar, a vast province that shares borders with Syria, Jordan, and Saudi Arabia.
In the mid-2000s, U.S. troops and their Sunni allies carried out two major operations to clear Anbar of insurgents.
Outside the province, Iraqi police said at least 23 Iraqi Army recruits were killed in a suicide bomb attack on January 9 at a military recruiting center in Baghdad. Officials said at least 30 others were injured.
With reporting by AFP and RFE/RL's Radio Free Iraq