A United Nations human rights expert on Monday called on countries to take steps against Myanmar’s junta through economic sanctions and an arms embargo following the execution of four democracy activists.

Myanmar’s ruling military announced on Monday it had executed four democracy activists accused of aiding “terror acts”, sparking widespread condemnation of the country’s first executions in decades.

Asked in an interview what should be done in response, U.N. Special Rapporteur on human rights in Myanmar Tom Andrews said: “There are a number of options and what we need to see is the international community start to seize them.”

“The first option, the best option, is for the U.N. Security Council to convene to pass a strong resolution of not only condemnation, but clear strategic action, sanctions, economic sanctions and arms embargo” and refer the case to the International Criminal Court, he added in the same interview from Washington.

He called for more support for the humanitarian response, which was just 10% funded, and more coordinated engagement with the shadow government in Myanmar the National Unity Government (NUG), which is leading efforts to undermine the junta.

Officials at Myanmar’s embassy in Washington and its diplomatic mission in Geneva did not immediately respond to requests for comment on Andrews’ remarks. The junta has previously defended the death sentences as justified and used in many countries.

Andrews also voiced concerns about further executions, saying “at least 140 people” had been sentenced to death.

“And so there is every indication that the military junta intends to continue to carry out executions of those on death row, as it continues to bomb villages and detain innocent people throughout the country,” he said.

Myanmar’s authorities have previously said they only use force when necessary to counter national security threats.

Sentenced to death in secretive trials in January and April, the four men executed were accused of helping a civilian resistance movement that has fought the military since last year’s coup and bloody crackdown on nationwide protests.

“I think it’s a demonstration to all of us that there are no limits to the depths of depravity of this military junta,” Andrews said.