Politico’s report indicates that as Iran’s war drags on, bipartisan support in the U.S. Congress for sanctions on Chinese banks that help keep the Islamic Republic’s financial flow going has increased.

According to Politico, a large share of Iran’s oil revenues depends on selling oil to China’s independent refineries, and Chinese banks play a role in transferring income from these deals. Some lawmakers believe that without targeting this financial network, economic pressure on Tehran will have limited impact.

However, sanctions on major state-owned Chinese banks could have wide-ranging consequences for the global financial system. Four of the country’s biggest banks hold about $25 trillion in assets, and cutting off their access to the U.S. financial system could affect banks and companies in the United States, Europe, and Asia.

The move also carries the risk of a retaliatory response from Beijing—something the Trump administration should consider ahead of next month’s meeting between Donald Trump and Xi Jinping. Despite these risks, Politico writes that fatigue over the Iran war and dissatisfaction with China’s role in preserving Tehran’s financial lifeline has increased Congress’s willingness to take on this risk.