PHOENIX, Arizona (AP) — The Trump administration on Wednesday unveiled new rules that will make it harder for children of some immigrants serving in the military to obtain citizenship.

US Citizenship and Immigration Services released updated guidance Wednesday that appears to mostly affect non-citizen service members but which caused confusion among immigration lawyers and advocates after a document appeared to show children of American citizens would also be affected.

Department of Defense spokeswoman Lieutenant Colonel Carla M Gleason said in a statement that the department worked closely with USCIS and “understands the estimated impact of this particular change is small”.

“However, we are committed to ensuring affected families are provided the appropriate information, resources, and support during this transition,” Gleason said.

The policy manual update is highly technical and contradicts parts of an 11-page memo the agency initially put out that implied American citizens were among those whose children would no longer be automatically granted citizenship if born abroad.

Agency spokeswoman Meredith Parker told the military news organization Task and Report that the policy change “explains that we will not consider children who live abroad with their parents to be residing in the United States even if their parents are US government employees or U.S. service members stationed outside of the United States, and as a result, these children will no longer be considered to have acquired citizenship automatically.”

Her boss, acting director Ken Cuccinelli, played down the changes in a Twitter statement, saying the update doesn’t deny citizenship to children of government and military members.

“This policy aligns USCIS’ process with the Department of State’s procedures for these children — that’s it. Period.”

The policy change is yet another roadblock that the administration of President Donald Trump has placed for people to live legally in the United States, said immigration attorney Martin W Lester, who is based in Tennessee and who serves on the military assistance committee of the American Immigration Lawyers Association.

It appears to target children of service members who are legal permanent residents and not US citizens, but could also affect citizens if they can’t prove they lived in the US for a certain amount of time. People in those scenarios would have to undergo a more cumbersome process for obtaining American citizenship for their kids.

“It’s gonna take time, money, it’s gonna cause stress. There’s gonna be some people whose kids aren’t gonna qualify and that’s gonna cause a huge problem,” Lester said.

Parker, the USCIS spokeswoman, repeatedly refused to answer questions from The Associated Press, referring only to Cuccinelli’s Twitter statement.

Immigrant advocates have said the Trump administration has unfairly treated members of the military who aren’t American citizens. The AP reported last year that the Army was quietly and abruptly discharging soldiers who enlisted through a special recruitment program that promised a path to citizenship.