Iran will partially pull out of the nuclear deal it signed with the United States and five other nations. Iranian President Hassan Rouhani said his country would reduce its “commitments” to the deal, signed in 2015, but wouldn’t completely withdraw. President Donald Trump pulled the United States out of the agreement — which was intended to prevent Iran from developing nukes — a year ago. Tensions between the two countries have ramped up in recent weeks: The United States moved to cut off Iran’s oil revenues, designated its Revolutionary Guard as a terrorist group and deployed a carrier strike group and a bomber task force to the Middle East in response to reported threats from Iran. Here are answers to four questions about Iran’s partial withdrawal.