TEMPO.CO, Kiev - Two major international watchdogs alleged that human rights abuses and war crimes have occurred in eastern Ukraine this year. The clashes between Russian-backed separatists and pro-Kiev forces have killed at least 3,500 people since April.

On Monday, October 20, 2014, Amnesty International reported that it has strong evidence that suggests both sides carried out extra-judicial killings. In one case, investigators found nine bodies in mass graves. Five of the dead appeared to have been pro-Russian separatists killed in battle, while the four others were "executed” by Kiev loyalist forces.

As reported by Voice of America, Human Rights Watch (HRW) also said that after a four week-long investigation in eastern Ukraine, the group documented "widespread use" of cluster bombs in clashes between separatists and government forces.

The New York based HRW added that evidence "points to Ukrainian government forces responsibility" for several cluster bomb attacks on the separatist stronghold of Donetsk.

Russia and Ukraine are not parties to the Convention on Cluster Munitions that prohibits their use entirely.

"It is surprising that a munition banned by many countries, are used extensively in eastern Ukraine. The Ukraine government should commit to ban their use by joining the convention," said Mark Hiznay, a senior weapons analyst for the HRW.

The Ukraine military however denied the report. "We do not use cluster bombs. The bombs can only be deployed from an aircraft and our aircrafts have been grounded since the cease fire on 5 September," said Ukraine military spokesperson Andriy Lysenko to Reuters, Tuesday, October 21, 2014.

VOICE OF AMERICA | REUTERS | DWI ARJANTO