New Delhi, Aug. 21 -- A coalition of unions and advocacy groups has sued the US government to block new rules that would impose fixed limits on how long international students, exchange visitors and foreign journalists can remain in the country without seeking an extension.

The lawsuit, filed on August 18 in the US District Court for the District of Massachusetts, challenges regulations issued by President Donald Trump's Department of Homeland Security (DHS). The groups argue that the changes could discourage international students and scholars from coming to the United States while creating additional uncertainty for foreign journalists.

Under the new DHS regulations, F visas for international students and J visas for exchange visitors...