Mira Resnick, deputy assistant secretary of state for regional security, testified in Congress that she could not say what would happen, but in the past, the State Department’s bureau of political and military affairs has been unable to process new licences or new military sales for any partner, including Taiwan, during a shutdown, except in an emergency.

“This is something we would like to avoid,” she told a House of Representatives hearing on defence cooperation with Taiwan.

The Republican-controlled House and Democratic-led Senate have until Oct 1 to avoid a partial shutdown by enacting appropriations bills that President Joe Biden can sign into law, or passing a short-term spending measure to give lawmakers more time for debate.

Fuelling fears of a shutdown, the House on Tuesday failed to move forward on a fiscal 2024 defence appropriations bill, as divisions among speaker Kevin McCarthy’s Republicans threatened Congress’ ability to fund the government before the deadline.

Separately, Pentagon spokesman Chris Sherwood said a shutdown could affect shipments to Ukraine. Delivery of defence articles, services, and training “could be impacted by furloughs of personnel and DoD’s suspension” of non-essential activities, Sherwood said in an emailed statement.

Sherwood’s comments were first reported by Politico.

At the United Nations on Tuesday, Biden appealed to world leaders to stand with Ukraine against Russian invaders.

Biden has made rallying allies to support countries like Ukraine and Taiwan a leading component of US foreign policy.

China’s military in recent years has stepped up activity around Taiwan, which Beijing claims as its territory. CIA director William Burns has said Chinese president Xi Jinping has instructed his military to be ready to invade by 2027.

Ukrainian president Volodymyr Zelensky will visit the US Capitol on Thursday and meet with members of Congress, who are considering Biden’s request for billions of dollars in additional military aid to Ukraine.