“The international community is fighting to stop a process that is alarmingly on track to potentially render millions of people stateless, and vulnerable to indefinite detention, violence or worse,” Mr. Patel said in the statement.

The list, which is called the National Register of Citizens but only applies to Assam, was last updated in 1951, and government officials have said the records are in desperate need of revision. Upamanyu Hazarika, a lawyer who works on migration issues, said the number of illegal immigrants living in Assam now reached into the millions.

But the decision to update the register has inflamed passions in Assam, where anti-immigrant protests in the 1980s culminated in the massacre of around 1,800 people in several Muslim villages. In the past few decades, the proportion of Bengali Muslims in Assam, home to over 30 million people, has climbed, but observers have pointed out that the jump could relate to higher birthrates among the Muslim community and not to migration from Bangladesh.

In December, the state government released an early draft of the citizenship list, which left out some 13 million people. In some cases, children were on the list, but parents or members of older generations who often do not have citizenship documents were not. Families said they feared being torn apart, and several suicides were linked to the long, bureaucratic process.

Monday’s draft shaved the number of excluded to four million, and Aman Wadud, an independent lawyer in Assam who works on migration cases, said, “no one has been rendered stateless.” The appeals process would continue, he said, and a date for the release of the final list has not been set.

“There is no mechanism to deport people and that question shouldn’t arise now,” he said in a telephone interview. “Just because your name is not there, doesn’t mean that you can’t cross the hurdle.”

In an interview with The Indian Express newspaper, Sarbananda Sonowal, the chief minister of Assam, said that the final list “will have names of all the genuine Indian citizens residing in the state.” Earlier this year, Mr. Sonowal said illegal immigrants would be immediately stripped of their constitutional rights.