It isn’t clear why PetroVietnam withdrew the application for American financial support for the Vietnamese coal plant, Long Phu 1. But the project, which is already under construction, faced intense criticism inside and outside the United States.

Environmental and other groups said the project would have had a greater environmental impact than reports submitted by PetroVietnam had suggested. More broadly, the application raised the question of whether the Trump administration’s commitment to using more coal at home would extend abroad.

The World Bank and other major institutions have increasingly avoided backing projects supported by developing countries that burn coal and other fossil fuels, which emit greenhouse gases that contribute to climate change. The United Kingdom’s version of the Ex-Im Bank had declined to offer financial support for the Long Phu 1 project for similar reasons.

In addition, the project is partly financed by Vnesheconombank, a Kremlin-connected Russian lender that has been subject to American sanctions since 2014 because of Moscow’s military intervention in Ukraine. On Jan. 26, the United States Treasury Department expanded its Russia sanctions to include Power Machines, a Russian firm that is one of several construction companies with contracts at Long Phu 1.

The Ex-Im Bank said in a statement that it had not yet completed its due diligence review of Long Phu 1 when the application was withdrawn. It also did not specify a date for the withdrawal and referred further questions to PetroVietnam.