WASHINGTON — The Trump administration announced on Wednesday that it intends to lift sanctions against the business empire of Oleg V. Deripaska, one of Russia’s most influential oligarchs, after an aggressive lobbying campaign by Mr. Deripaska’s companies.

The decision by the Treasury Department, which had been postponed for months, was both politically and economically sensitive, and drew criticism from some Democrats and foreign policy analysts that the administration was sending the wrong signal to Moscow about its conduct toward its neighbors and the United States.

The companies are among the biggest in the aluminum industry, and questions about their fate had roiled global metals markets. And Mr. Deripaska’s stature in Russia made any decision seen to be in his favor tricky for the administration at a time when President Trump is under investigation by the special counsel in connection with Russian interference in the 2016 election.

Mr. Deripaska and his businesses — including the world’s second-largest aluminum company, Rusal — were hit with sanctions in April in retaliation for Russian interference in the election and other hostile acts by Moscow.