President Donald Trump issued a proclamation Friday to deny asylum to migrants who enter the country illegally, tightening the border as caravans of Central Americans slowly approach the United States. The plan was immediately challenged in court.

Trump invoked the same powers he used last year to impose a travel ban that was upheld by the Supreme Court. The new regulations are intended to circumvent laws stating that anyone is eligible for asylum no matter how he or she enters the country. About 70,000 people per year who enter the country illegally claim asylum, officials said.

“We need people in our country, but they have to come in legally,” Trump said Friday as he departed for Paris.

The American Civil Liberties Union and other legal groups swiftly sued in federal court in Northern California to block the regulations, arguing the measures were illegal.

“The president is simply trying to run roughshod over Congress’s decision to provide asylum to those in danger regardless of the manner of one’s entry,” said ACLU attorney Lee Gelernt.

The litigation also seeks to put the new rules on hold while the case progresses.

The regulations go into effect Saturday. They would be in place for at least three months but could be extended, and don’t affect people already in the country. The Justice Department said in a statement the regulations were lawful.

Trump’s announcement was the latest push to enforce a hard-line stance on immigration through regulatory changes and presidential orders, bypassing Congress, which has not passed any immigration law reform. But those efforts have been largely thwarted by legal challenges and, in the case of family separations this year, stymied by a global outcry that prompted Trump to retreat.

When a 10-year-old Wisconsin girl was charged with homicide this week in the death of an infant, it was a rare — but not unprecedented — case of adult charges being filed against someone so young.

The girl told investigators she panicked after dropping the baby at a home day care and then stomped on his head when he began crying. She sobbed during a court appearance in Chippewa County, where she was led away in handcuffs and a restraint.

The age at which children get moved to adult court varies by state and can be discretionary in some cases.

Wisconsin is an outlier in that state law requires homicide or attempted homicide charges to be initially filed in adult court if the suspect is at least 10 years old, according to Marcy Mistrett, chief executive at the Campaign for Youth Justice.

Wisconsin is among 28 states that allow juveniles to be automatically tried in adult court for certain crimes, including murder. For most states, the age at which that is triggered is 15 or 16 years old — while some states have decided 10 is even too young for a child to be held responsible in the juvenile justice system, Mistrett said.

Moving a case to juvenile court depends on establishing certain factors, such as whether the child would get needed services in the adult system, said Eric Nelson, a defense attorney who practices in Wisconsin.

For example, prosecutors in an attempted murder case involving a 12-year-old schizophrenic girl who stabbed a classmate said she belonged in adult court, where she could be monitored for years for a disease that isn’t curable. Defense attorneys unsuccessfully argued against those claims.

Homicide cases involving 10-year-old defendants are extremely rare. From 2007 through 2016, 44 children aged 10 or younger were believed to be responsible for homicides in the U.S., according to data compiled by Northeastern University criminologist James Alan Fox. Only seven of those children were girls.

In 2003, two 12-year-old boys fatally beat and stabbed 13-year-old Craig Sorger after they invited him to play in Washington state. Evan Savoie and Jake Eakin ultimately pleaded guilty in adult court and were sentenced to 20 years and 14 years in prison, respectively.