The United Nations (UN) special envoy to Myanmar on Friday urged the Security Council to act to quell junta violence that this week killed about 50 demonstrators and injured scores more.

“There is an urgency for collective action,” Christine Schraner Burgener told the meeting. “How much more can we allow the Myanmar military to get away with?”

Coordinated UN action is difficult, however, since permanent Security Council members China and Russia would almost certainly veto it. Myanmar’s neighbors, its biggest trading partners and sources of investment, are likewise reluctant to resort to sanctions.

Some piecemeal actions have already been taken. The US, Britain and Canada have tightened various restrictions on Myanmar’s army, their family members and other top leaders of the junta. The US blocked an attempt by the military to access more than $1 billion in Myanmar central bank funds being held in the US, the State Department confirmed Friday.

But most economic interests of the military remain “largely unchallenged,” Thomas Andrews, the UN special rapporteur on the rights situation in Myanmar, said in a report issued last week. Some governments have halted aid and the World Bank said it suspended funding and was reviewing its programs.

Its unclear whether the sanctions imposed so far, although symbolically important, will have much ímpact. Schraner Burgener told UN correspondents that the army shrugged off a warning of possible “huge strong measures” against the coup with the reply that, “‘We are used to sanctions and we survived those sanctions in the past.’”

Andrews and other experts and human rights activists are calling for a ban on dealings with the many Myanmar companies associated with the military and an embargo on arms and technology, products and services that can be used by the authorities for surveillance and violence.

POTENTIAL ECONOMIC SANCTIONS

The activist group Justice for Myanmar issued a list of dozens of foreign companies that it says have supplied such potential tools of repression to the government, which is now entirely under military control.

It cited budget documents for the Ministry of Home Affairs and Ministry of Transport and Communications that show purchases of forensic data, tracking, password recovery, drones and other equipment from the US, Israel, European Union, Japan and other countries. Such technologies can have benign or even beneficial uses, such as fighting human trafficking. But they also are being used to track down protesters, both online and offline.

Restricting dealings with military-dominated conglomerates including Myanmar Economic Corp., Myanmar Economic Holdings Ltd. and Myanmar Oil and Gas Enterprise might also pack more punch, with a minimal impact on small, private companies and individuals.

One idea gaining support is to prevent the junta from accessing vital oil and gas revenues paid into and held in banks outside the country, Chris Sidoti, a former member of the UN Independent International Fact-Finding Mission on Myanmar, said in a news conference on Thursday.

Oil and gas are Myanmar’s biggest exports and a crucial source of foreign exchange needed to pay for imports. The country’s $1.4 billion oil and gas and mining industries account for more than a third of exports and a large share of tax revenue.

“The money supply has to be cut off. That’s the most urgent priority and the most direct step that can be taken,” said Sidoti, one of the founding members of a newly established international group called the Special Advisory Council for Myanmar.