The US has hailed the creation of a new government in Iraq as a major milestone and a crucial step towards defeating the militant group, Islamic State (IS).
Secretary of State John Kerry said Prime Minister Haider al-Abadi's cabinet had the "potential to unite all of Iraq's diverse communities".
Posts have been shared between the Shia Arab majority, Sunni Arabs and Kurds.
Mr Kerry is travelling to Saudi Arabia and Jordan this week as part of efforts to build a coalition to confront IS.
The jihadist group has taken control of large swathes of Iraq and Syria and in June declared the creation of a "caliphate", or Islamic state.
Among the first to telephone Mr Abadi to congratulate him was US President Barack Obama, who hopes the new government can start pulling Iraq back together.
The two leaders "agreed on the importance of having the new government quickly take concrete steps to address the aspirations and legitimate grievances of the Iraqi people", a White House statement said.
The US had made the approval of a unity government a condition for increased military assistance.
Mr Abadi, a Shia, named three deputies - Hoshyar Zebari, the Kurdish outgoing foreign minister, Saleh al-Mutlak, a secular Sunni who held the same post in the last government, and Baha Arraji, a Shia and former MP.
Analysis: Jim Muir, BBC News, Irbil
The Americans are hoping the new government can start pulling Iraq back together, and provide a springboard for a national drive to root out Islamic State militants. That can only work if the Sunni community can be persuaded that that is in their interests.
Mr Obama and Mr Abadi agreed on the need for the new government to address the aspirations and legitimate grievances of the Iraqi people - a clear reference to the Sunnis. Their demands include the release of detainees, an end to bombardment of Sunni areas, and a real share of power in Baghdad.
The task ahead is clearly massive. Among other things, the Iraqi army is in a state of disarray, and much of the recent fighting has been done by Shia militia, strengthening the element of sectarian civil strife that will have to be eliminated if the IS radicals are to be isolated and crushed, without whole communities being destroyed.
Adel Abdul Mahdi, a Shia former vice-president, was appointed oil minister and former PM Ibrahim Jaafari, also Shia, will be foreign minister. No defence or interior minister was named but Mr Abadi promised to do so within a week.
He vowed to "allow all people in Iraq to participate in liberating the cities and provinces which have been taken over by terrorist groups... and to bring back security and stability".
The BBC's Jim Muir in Irbil says the hope is that by including Sunnis, the new administration can win the support of the Sunni population in areas controlled by IS and turn them against the radicals.
Iraqi government: Key appointments
- President: Fuad Masum, veteran Kurdish politician
- Vice-Presidents: Nouri Maliki, Shia former prime minister, and two of his powerful political rivals - Iyad Allawi, a Shia former PM, and Usama al-Nujaifi, the Sunni former speaker of parliament
- Prime Minister: Haider al-Abadi, Shia former deputy speaker
- Deputy Prime Ministers: Hoshyar Zebari, Kurdish ex-foreign minister, Saleh al-Mutlak, a Sunni who held the same post in the last government, and Baha Araji, a Shia MP
- Foreign Minister: Ibrahim Jaafari, Shia former prime minister
- Finance Minister: Rowsch Shaways, Kurdish former deputy PM
- Oil Minister: Adel Abdul Mahdi, Shia former vice-president
- Defence & Interior Ministers: MPs given a week to agree appointees before Mr Abadi will fill the posts with his own choices
Many Sunnis were alienated by the outgoing Shia-dominated government of Nouri Maliki and rebelled against it.
Later, Mr Kerry told reporters in Washington: "Iraq's leaders must now govern with the same sense of purpose that helped them bring this government together."
"The defeat of [IS] will be a long-term challenge but Iraq will have the support of the United States and its other friends and allies, as it rises above its differences, strengthens its democratic institutions, meets the needs of its vulnerable citizens, combats terrorism, and unites in its resolve against [IS]," he added.
Iraqi media reaction
Al-Bayan, a newspaper linked to the Daawa Party of former PM Nouri Maliki, declares that "Iraq has entered a new era".
For al-Sabah, the approval of the government "under the new democratic system" is proof that "so far, we have successfully passed all the tests set by the political process".
Some papers are worried that defence or interior ministers were not appointed. "Abadi gains parliament's confidence with an incomplete government," reads the main headline of al-Dustur.
Pro-Sunni Baghdad TV says "foreign pressure" caused the government to be formed on time, and broadcasts interviews with Iraqis who feel the new government "is not different" from previous administrations.
The state department said Mr Kerry would travel to the Middle East on Tuesday to consult key partners on how to further support the Iraqi government, combat the threat posed by IS, and confront regional security challenges.
He was expected to hold talks with the foreign ministers of Iraq, Egypt, Jordan, Lebanon and six Gulf Arab states in the Saudi city of Jeddah on Wednesday and Thursday, Arab officials said.
Mr Obama will also unveil his strategy to combat IS on Wednesday.
He has ruled out the possibility of a US ground operation but sanctioned dozens of air strikes against the group in Iraq and reconnaissance flights over Syria.
"Over the course of months, we are going to be able to not just blunt the momentum of [IS]," he said on Sunday. "We are going to systematically degrade their capabilities; we're going to shrink the territory that they control; and, ultimately, we're going to defeat them."