Iraq’s prime minister, Ali al-Zaidi, pledged to disarm his country’s Iran-backed militias by June 2027, laying out an exceptionally ambitious timeline for bringing the country’s unwieldy array of militants under state control. The phased disarmament plan, which Mr. al-Zaidi laid out for the first time in an interview with The New York Times on Saturday in Baghdad, would be central to how Iraq manages the delicate balancing act between its two most important allies, the United States and Iran, at a time when those countries are at war.

Iraq is under mounting pressure from the Trump administration, its most critical security and economic partner, to defang the Iran-aligned forces, which have accrued not only military might, but also political power. At the same time, Iran, Iraq’s neighbor, is seeking to deepen its influence in the country and expand the use of those militias in the war with Washington. Disarming the militias has bedeviled previous Iraqi leaders, including those with far more experience than Mr. al-Zaidi in the country’s fractious political scene. Iran-backed factions have become increasingly entrenched over recent years, forming parties that are enmeshed in Iraq’s political and economic system and making their containment a daunting task.

“This is not something that is optional. It is a necessity,” Mr. al-Zaidi said of his disarmament plan, in his first interview with foreign news media at his official residence. “Others who spoke of this then backtracked,” he said. “They yielded to pressure or to other concerns. For me, this issue, along with that of corruption, is a matter of honor.” The difficulties have not deterred Mr. al-Zaidi, who was a political novice before becoming prime minister this year. Before his nomination, the wealthy businessman was largely unknown to most Iraqis. This week, as Mr. al-Zaidi will attend his first United Nations General Assembly, he is confronting not only a security challenge, but also a daunting economic crisis. Iraq, the world’s third-largest supplier of oil, has lost 60 percent of its monthly export revenue because of the war between the United States and Iran, which has choked off shipping through the Strait of Hormuz, Mr. al-Zaidi said. Since taking office, he has been pitching proposals to build pipelines that would bypass the Persian Gulf, including one that he said could reach Europe. “We wish to build bridges and economic ties between Iraq and the countries of the world,” he said. “Under this government, Iraq will be a meeting point, not a point of hostility.” Realizing these aspirations, however, will depend on Mr. al-Zaidi’s meeting the Trump administration’s demand that he rein in the militias. “Arms have to be confined first so you can build a solid economy,” he said.