President Joe Biden has signed into law a package of US security measures including tougher measures targeting Iran’s oil trade with China.

The law is focused on $61bn of military support for Ukraine and $26m for Israel but also includes closer scrutiny of ships, refineries and insurers linked to the Iran oil trade.

The measures were passed by the House of Representatives and the Senate and signed off by Biden within five days.

The measures under the Stop Harboring Iranian Petroleum Act require the president to impose asset freezes and travel bans for non-US citizens who knowingly move, refine and deal with Iranian crude and products.

The administration also has to report annually on the scale of the trade and the refiners and ships involved, including details on ship-to-ship transfers.

Most Iranian oil is shipped to China, where it is used by small private “teapot” refineries.

Total Iranian exports stood at 1.5m barrels per day in March, close to the highest levels under sanctions since 2018 and despite high-profile designations aimed at hitting the trade.

Analysts have said the measures are likely to be limited in scope. The president will able to impose waivers to limit their impact.