BOSTON (AP) — Some immigrants living in the country illegally and accused of crimes sit in legal limbo, caught in a tug of a war between local prosecutors and federal immigration authorities who won't let them appear in court because they fear being denied the opportunity to deport them.

Advocates for immigrants say the hardball tactics of Immigration and Customs Enforcement are blocking due process rights, creating chaos and forcing runarounds in court systems to get immigrants who are accused of crimes in front of judges.

Under Republican President Donald Trump, the agency is specifically targeting suspects not yet found guilty, a departure from the Obama administration, which focused primarily on those convicted, attorneys say. Advocates argue ICE has also sometimes used criminal allegations against immigrants in their deportation efforts without letting them answer the charges.

"This is now becoming a kind of full-fledged war between the federal government and states and localities," said Muzaffar Chishti, director of the Migration Policy Institute's office at New York University School of Law.

While it's unclear how many defendants are not being turned over to appear in court, cases are popping up around the country, largely in so-called sanctuary cities and states where local authorities don't cooperate with the federal government on immigration enforcement.

ICE doesn't track how many detainees have pending criminal charges or how often they're denied release to state custody for court proceedings, an agency spokeswoman said.