People who visit New Jersey from states where COVID-19 cases are spiking will have to quarantine for 14 days.

Gov. Phil Murphy made the announcement Wednesday along with the governors of Connecticut and New York. The quarantine requirements impact those states as well. The governors said that they need to protect the progress the tristate area has made against the virus.

“This is not a polite recommendation, this is a strong advisory,” Murphy said.

States with high rates of infection are those with more than 10 COVID-19 cases per 100,000 people on a seven-day rolling average and states with a seven-day positivity average of 10% or higher. Currently this would impact travelers from nine states, including Arizona, Florida and Texas.

“We don’t want to see the infection rate increase here after what we’ve gone through,” said New York Gov. Andrew Cuomo.

“Our three states are among only four listed by researchers and experts at COVID Act Now as being close to containing the virus,” Murphy said.

Cuomo said that those who violate the quarantine order in New York could be fined. Murphy said that he won’t do that and admits that enforcing the quarantine will be challenging.

“We’re not able to put border checks around New Jersey. It’s just not – travel from one state to the next is something that’s allowed,” Murphy said.

The announcement comes as New Jersey continues to advance toward the final state of reopening. Murphy announced that libraries, museums and entertainment establishments like arcades can reopen at 25% capacity on July 2.

“Inside is a whole different reality than outside,” Murphy said.

Gyms can partially reopen on July 2, but only for individual training and by appointment only.

"As with all other indoor activities the wearing of face coverings or masks is and will be required,” Murphy said.

The quarantine requirement takes effect at midnight.