Russian President Vladimir Putin has ordered special services to "find and destroy" the killers of four Russian diplomats taken hostage in Iraq.
Mr Putin hopes Russia's friends will help identify the killers
The head of Russia's security services immediately pledged to see Putin's order carried out.
The Russian government confirmed the four men's deaths this week, after an insurgent group released a video showing two of them being killed.
The group had demanded Russia leave Chechnya and release Muslim prisoners.
"The President gave the order to Russian special services to take all measures for finding and eliminating the criminals who carried out the murder of Russian diplomats in Iraq", the Interfax news agency quoted the Kremlin's press service as saying.
He said Russia hoped its friends would help to identify the killers.
The head of the Federal Security Service (FSB), Nikolai Patrushev, promised to carry out the task "however much time and effort it requires", Interfax reported.
Separately, the lower house of the Russian parliament approved a statement condemning the killings, and appearing to blame Iraq's "occupying powers".
"The whole responsibility for the situation in Iraq, including guaranteeing the security of its citizens, and also foreign specialists, as before lies on the occupying powers," the statement said
Russia has strongly opposed the US-led military campaign from the beginning.
The diplomats were seized in Baghdad on 3 June.
A group called the Mujahideen Shura Council, linked to al-Qaeda in Iraq, posted the video of the killings on the internet.
On Monday, the Russian foreign ministry urged the Iraqi authorities and the US-led coalition forces to find and punish the perpetrators.