Kerry also pledged USD 155 million in new US aid to Iraq.
Making an unannounced visit to Baghdad, his first in two years, Kerry held discussions with Prime Minister Haider al-Abadi as well as with Iraq's foreign minister, the Sunni speaker of parliament and a Kurdish regional leader in what was designed as a show of support for the Iraqi government as it struggles with ongoing security, economic and political challenges.
"It is important to have stability," Kerry told reporters.
"And it is important to have a unified and functioning government as soon as possible, so that these operations are not affected."
Kerry's trip coincides with military advances.
Iraqi forces say they entered the strategically important IS-held town of Hit yesterday, while the Pentagon is considering establishing more small military outposts to provide artillery support and other aid to Iraqi forces readying an assault on Mosul, Islamic State's stronghold in the country.
But al-Abadi faces challenges of his own.
Al-Abadi proposed a new cabinet line-up amid mounting pressure from supporters of a hard-line Shiite cleric who last month staged rallies and a sit-in next to the government headquarters to demand reforms.
But the move was quickly met with broad opposition, making it unlikely that al-Abadi will be able to obtain confirmations for the key political posts.
"We don't play a role in that," Kerry said, trying to emphasize neutrality.
Kerry outlined significant remaining work - not least the long-delayed offensive to chase the extremists out of Mosul, Iraq's second largest city.
He offered no time frame for when the actual assault might begin, and he stressed that no additional American forces are being considered. There are 3,870 U.S. Forces in Iraq currently, though the number fluctuates.
"There was no request from Prime Minister Abadi for some new infusion of troops at this point in time, and nor did we discuss that," Kerry said.
