Moscow ( CNN ) -- Just before Syrian security forces launched a large-scale military operation in the southern town of Daraa in the early hours of April 25 , the commander of the 35th Special Forces Regiment , Brig . Gen. Ramadan Mahmoud Ramadan , allegedly gathered his troops and explained their mission . `` Use heavy shooting . Nobody will ask you to explain , '' the brigadier said , according to `` Amjad , '' one of the many defectors I have interviewed in the last months . Amjad explained to me that normally the troops were supposed to save bullets , but this time it was different . `` The commander said to use as many bullets as we wanted . '' Over the next four days , security forces in Daraa killed around 200 people ( Human Rights Watch documented the abuses at the time by interviewing victims and witnesses ) and arrested thousands , subjecting many to beatings and torture . Since then , Amjad and more than 60 other defectors from Syria 's military and intelligence agencies have given us crucial information about who was responsible for abuses across the country . They provided consistent accounts of officers giving similar orders to military units all over Syria , at different times . The orders were to stop the protests `` by all means necessary . '' In many cases , they said , officers gave orders to fire directly at protesters . The defectors told us that some soldiers reacted by throwing away their weapons and making a run for it . Others aimed above the protesters ' heads or to the ground . But that was dangerous . Eight defectors told us that they saw officers and intelligence agents killing soldiers who disobeyed orders . Others were detained and tortured . We are not publishing the defectors ' names and locations to protect them and their families . All these statements demolish President Bashar al-Assad 's claim that the bloodshed is the result of a few rogue commanders getting overly enthusiastic on crowd control . The defectors ' testimonies paint a horrific picture of a widespread and systematic crackdown against demonstrators : torture , arbitrary arrests and a `` shoot to kill '' policy that clearly amount to crimes against humanity . Al-Assad and his allies have sought to portray the protesters as `` armed gangs sponsored from abroad . '' In more than nine months of investigations in Syria , we have documented episodes of fighting , and attacks on security forces by armed defectors have increased . But the vast majority of protests that we documented were nonviolent , and the government 's use of force was clearly excessive compared with any threat facing troops . The Syrian leadership has so far gotten away with murder , in part because the Russian government , one of Assad 's staunchest allies , has blocked action on Syria at the U.N. Security Council and continues to supply Syria with arms . The Syrians whom I interviewed were well aware of Russia 's obstructionist position . As Ghassan , a former officer , was serving tea during our interview , he suddenly stopped and looked at me with suspicion . `` I heard you are Russian -- if you say that you support their position on Syria , you wo n't get any tea ! '' He was joking , of course , but his anger at Russia was real . Since Russia blocked Security Council action in October , Syrian security forces have killed more than 2,000 people , according to the U.N. high commissioner for human rights , Navi Pillay . Russia 's continued obstruction sends a signal to the Syrian government that it can continue its violent crackdown with impunity . It is difficult to conduct human rights investigations on Syria , since the government has barred most journalists , human rights monitors and even a U.N. commission of inquiry . But it is not impossible . I managed to enter Syria and speak safely with victims there , and we continue to interview witnesses in neighboring countries . We 've spoken to hundreds of Syrians with firsthand knowledge of abuses . And in a report Human Rights Watch released Thursday , we 're naming 74 commanders , from generals to colonels to captains , who allegedly ordered , authorized or condoned the abuses . But responsibility for these crimes does not stop with the commanders on the ground . Under international criminal law , al-Assad , as commander in chief of all forces in Syria , bears responsibility for the most serious crimes committed by his forces -- even if he did not order them -- to the extent that he knew or should have known about the abuses and failed to prevent them . Given the widespread public and international criticism of the abuses , it would be incredible for al-Assad to argue that he did not know . Pillay told the Security Council this week that the death toll in Syria tops 5,000 , including 300 children killed . Amjad 's commander may have told his troops that `` nobody will ask you to explain , '' but he was wrong . It 's time for the Security Council to act : to impose an arms embargo on Syria , to apply targeted sanctions to al-Assad and his circle of cronies , and , most important , to refer Syria to the International Criminal Court in The Hague . That is where Ramadan , his fellow commanders and his bosses will have to explain themselves and where their many victims will receive justice . The opinions expressed in this commentary are solely those of Anna Neistat .
Anna Neistat : Defectors say Syrian military told them to use ` ` heavy shooting '' in the attack . She says al - Assad must take responsibility for killings , torture ##s by defectors . She says Russia has helped with Security Council action . Neistat : Syria must face arms embargo , sanctions , referral to International Criminal Court .