The U.S. Embassy in Kyiv is warning dual U.S.-Ukrainian citizens they will no longer be able to depart the war-torn country if they are otherwise eligible for conscription.

Under Ukraine’s martial law, men aged 18 to 60 are prohibited from leaving the country, but dual citizens had previously been able to circumvent this rule by deregistering their Ukrainian residency before leaving and registering their U.S. residency.

As of June 1, however, Ukraine has eliminated this “residence abroad” loophole and dual citizens now face “an extremely high risk you will not be allowed to depart, even with a U.S. passport,” the U.S. embassy said in a notice issued Tuesday.

“Ukrainian law does not recognize dual citizenship. U.S.-Ukrainian dual citizens are therefore treated solely as Ukrainian citizens while in Ukraine and are subject to the rights and obligations of Ukrainian citizens,” the notice read.

The U.S. embassy said it is “limited” in its ability to influence Ukrainian law or Kyiv’s efforts to draft citizens into its armed forces amid the war with Russia.

For dual citizens who are not currently in Ukraine “who do not wish to stay in Ukraine indefinitely,” the U.S. embassy advised against all travel to the country.

“If you are in Ukraine and cannot leave the country, shelter in place and obey all local orders,” the U.S. embassy advised.

Ukrainian President Volodymyr Zelensky in April signed the controversial mobilization law aimed at boosting the country’s depleted forces as it battles Russia.

The country has taken other steps to boost conscription, including not allowing fighting-age men to renew passports from outside Ukraine.