Brig. Gen. John B. Richardson IV, a top US commander in northern Iraq, has said officials fear the longer the battle drags on, the deadlier it will become, especially for civilians. While there, the US troops also advised the Iraqis on how to secure the area, Sylvia said.
Iraqi forces pushed further into the IS stronghold Mosul from the north on the second day of a new push to speed up the anti-IS campaign, commanders said on Friday.
The US official said there is no talk of "creating independent American bases in Iraq", as the move would require thousands more personnel. The bill would fund the government until the end of September 2017.
The US now has close to 7,000 troops in the country, assisting Iraqi forces in the fight against IS.
On February 19, Iraqi troops started an onslaught to regain western Mosul from Islamic State, nearly a month after they recaptured the eastern part of the city. "We are still advancing to liberate the other neighborhoods", the officer said.
Mattis made it clear that USA involvement will not end when Mosul is finally captured from IS. "We scan, we take a look, we make sure", Browning said.
The Iraqi army said on April 30 that it aimed to finish the battle for Mosul, the largest city to have fallen under Islamic State control in both Iraq and Syria, this month.
Around half a million people died in Iraq from war-related causes during the US-led intervention between 2003 and mid-2011, according to a study published in 2013.
Meanwhile, the bulk of the Iraqi force, including the elite, US -trained Counter-Terrorism Service and federal police units, advanced from the city's southern outskirts. That number dropped to 40,000 before complete troop withdrawal in 2011.
Originally, the USA anti-IS campaign, which was launched in 2014 after Mosul fell to the militant group, was primarily focused on providing air support and military expertise. Iraq's military has not released any information on casualties.
The US has maintained a powerful military presence in countries across the Middle East for years, and the Trump administration does not seem likely to reverse that trend.
It said the targets of the latest push were northwestern neighbourhoods on the edges of Mosul called Musharifah, Kanisah and Al-Haramat.
If the long-term presence of United States troops in Iraq comes about, it would represent another Trump administration reversal of a key Obama administration initiative.
Some were killed accidentally covering military operations against the Islamic State group, some were murdered by the jihadists and others were assassinated in yet to be elucidated circumstances.