The announcement via Twitter comes as Trump’s U.S.-Mexico border wall fight with Democrats in Congress has kept the federal government closed for 21 days. The president’s tweet made no reference to the bitter stalemate over funding the wall, which he argues will curb illegal immigration and make the U.S. safer from violent foreigners.

Trump said holders of H1-B visas by professionals could “rest assured that changes are soon coming which will bring both simplicity and certainty to your stay, including a potential path to citizenship.”

H1-B visas are temporary work permits issued to highly-educated immigrants who work in specialized fields, often in technology. In 2016, a mere 20 companies were responsible for 37% of the workers who held them.

Trump’s vow to streamline the H1-B process comes after rules under which the visas are issued were tightened in 2018 by the U.S. Citizenship and Immigration Service. In a policy memo, the agency outlined a number of new requirements, which could deter companies and visa applicants.

Applications for H1-B visas have been falling, although demand still far outstrips supply. Each year, only 85,000 H1-Bs are issued to for-profit companies—a limit that has not been revised since 2005. Nonprofits, including hospitals and research institutions, are exempt from the cap.

Trump did not offer any specifics about what H1-B changes to expect and the White House did not expand on the president’s tweet.

H1-B holders in the United States can rest assured that changes are soon coming which will bring both simplicity and certainty to your stay, including a potential path to citizenship. We want to encourage talented and highly skilled people to pursue career options in the U.S.

— Donald J. Trump (@realDonaldTrump) January 11, 2019