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Secretary of State John Kerry, emerging from meetings in Baghdad with Iraqi leaders, said he's been assured by embattled Prime Minister Nouri al-Maliki that Iraqi lawmakers will meet in the coming days to form a new government -- though there's no guarantee the next government would look dramatically different.

"This is a critical moment for Iraq's future," Kerry said Monday, calling for "unity" in the face of a militant force threatening to tear the country apart.

The secretary pledged U.S. support for Iraqi forces, while stressing that a new government must be formed.

"The support will be intense, sustained, and if Iraq's leaders take the necessary steps to bring the country together, it will be effective," Kerry said.

The secretary said Maliki, with whom he met, "affirmed his commitment" to a July 1 session where Iraqi representatives will choose a speaker, a president and, ultimately, a prime minister.

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    "He committed to try to move that process as expeditiously as possible," Kerry said.

    It's unclear whether Maliki would stay on at the helm of the government.

    Iraq already was set to establish a new parliament and cabinet, following the certification last week of the April 30 election results. Kerry was nudging the country to move more quickly in a bid to ease sectarian tensions.

    While Maliki did not capture an outright majority in the elections, his party won the plurality of seats and in ordinary circumstances would be favored to retain control of the prime minister's seat.

    The advances of the Islamic State of Iraq and Syria (ISIS) have fueled U.S. calls for a new and "genuinely inclusive" government -- the Obama administration, though, has not explicitly called for Maliki to step down.

    Kerry spoke after flying into Baghdad for his first visit to Iraq since an army of Sunni insurgents began seizing major cities in an advance toward the capital.

    The secretary held a series of critical meetings with key Iraqi politicians, in an effort to prod them towards the swift formation of a new central government.

    With tensions in Iraq running high, security for the secretary's visit was extremely tight, with journalists accompanying him forbidden from reporting his trip to Baghdad until the C-17 military plane that transported the traveling party from Amman, Jordan touched down at the airport outside the capital.

    Kerry met with Maliki at the latter's residence, with the Iraqi foreign minister and other senior officials present, for an hour and 40 minutes. "That was good!" Kerry could be heard exclaiming, as he and his delegation exited. Hours earlier, however, fighters from ISIS had recently captured new territory at border crossings near Syria and Jordan.

    A senior State Department official, briefing the reporters traveling with Kerry via a background conference call conducted from Iraq, described Maliki, a Shiite, and other senior figures in the Iraqi government -- regardless of religious affiliation -- as deeply unnerved by the ISIS offensive. ISIS is designated by the State Department as a terrorist organization.

    "They're also very fearful of their situation," the official said. "A lot of people they've known, on the Sunni and the Shia side, over the last ten days have been killed ... Prominent leaders, their houses are gone ... And the limitations of the Iraqi security forces is [sic] very apparent ... They're very limited in the air. They have two Cessna planes that can fire Hellfire missiles. That's it, and they can't be everywhere at once. They have a limited number of helicopters. So their ability to respond to events when they are getting frantic calls from people who might be stranded or might be - it definitely takes a toll."

    Even on the American side, officials displayed a degree of uncertainty as to how to conceptualize the enemy fighters. Where senior aides traveling with Kerry on this trip had previously termed ISIS "a highly capable and sophisticated terrorist organization [that] is also essentially a criminal syndicate," the official briefing reporters from Baghdad, betraying the benefit of a more informed, ground-level view of the crisis, pointedly instructed reporters to take a different view.

    "It's really important to understand that it's an army," the briefer said. "There are political grievances in this country and that's a serious problem and we need to address them in order to mobilize the population to really stand up to these guys. But it's an army."

    Fox News' James Rosen contributed to this report.