Iran is once again under UN sanctions after three European countries announced the imposition of the snapback mechanism, accusing Iran of breaching its commitments over its nuclear programme.
UN sanctions were previously lifted under the Joint Comprehensive Plan of Action (JCPOA) in 2015 agreed between Iran and the UK, Germany, France - known as the E3 - alongside the US, Russia and China.
The plan placed a cap on Iran's nuclear enrichment at 3.67 percent, and a reduction in the stockpile of enriched uranium to 300kg, as well as allowing inspectors from the International Atomic Energy Agency to inspect sites.
The US withdrew from the JCPOA in 2018, with Iran believed to be exceeding its limits on nuclear enrichment and stockpiling following the withdrawal, although sanctions were not reimposed as international inspectors continued to have access to Iran's nuclear programme.
However, Iran suspended inspections after Israel launched a surprise attack against Iran's nuclear and military sites in June, with the US later joining in the 12-day war to bomb the underground site of Fordow.
Iran's President Masoud Pezeshikan reiterated last week that Tehran had no intention of developing nuclear weapons and has slammed the reintroduction of sanctions as "unfair, unjust, and illegal".
Economic sanctions
There are several UN sanctions, which were imposed between 2006 and 2010, that have come back into force and which all UN member states are obliged to uphold.
Resolution 1696 demands that Iran suspend its nuclear enrichment and urges states to block nuclear and missile transfers to the country.
Resolution 1737 bans the stockpiling of nuclear and missile technology, and freezes assets of individuals and companies related to the enrichment programme.
Resolution 1747 bans Iranian arms exports, and expands the asset freeze placed under 1737. It also urges states and international financial institutions to not extend loans or financial aid, with an exemption for humanitarian reasons.
Resolution 1803 allows for cargo inspections, tightens oversight on Iranian banks, and adds designations on Iranian nationals and dual-use nuclear items.
Resolution 1835 reaffirms previous measures.
Resolution 1929 expands an arms embargo onto conventional heavy weapons and restricts shipping, insurance and financial services linked to the nuclear and missile programme.
The resolution also prohibits Iranian investments in sensitive industries abroad, blocks foreign investment into Iran’s oil and gas industry, and creates a panel to monitor compliance.
Sanctions are expected to further impact Iran's economy, which has been suffering under years of US-imposed sanctions, as well as the government's fiscal situation.
Trading sites Bonbast and AlanChand reported that Iran's rial was trading at 1.12 million rials per dollar on the black market. A month prior, the rial was trading just above 1 million rials per dollar.