Jerusalem (CNN) -- Two of nine mortars fired from Gaza into Israel on Wednesday contained white phosphorous, Israeli police told CNN.
Bomb disposal experts examined the mortars and confirmed that two contained white phosphorous, a police spokesman said.
It was not the first time that Hamas has attempted to target Israel using mortars containing white phosphorous, the spokesman said.
White phosphorus ignites and burns, creating white smoke when it is exposed to oxygen. Militaries use it as a smoke screen to protect troops during combat. If it comes in contact with skin, however, white phosphorus creates an intense and persistent burn.
Israel itself has been roundly criticized for firing white phosphorus shells over densely populated areas during the Gaza offensive that began in late 2008.
However, in a July report to the United Nations, Israel pledged to limit the use of munitions containing white phosphorus and to make greater efforts to protect civilians during conflicts.
The latest allegations and violence come amid a fresh round of Middle East peace talks that began Tuesday in Egypt and continued Wednesday in Jerusalem.