Despite a skyrocketing death toll and new attacks from the Islamic State in Syria, Russian president Vladimir Putin on Thursday cheered his military's achievements there.

"The [Syrian] statehood has strengthened, as well as the government structures and the armed forces of the Syrian Republic," Putin told a media forum in St. Petersburg. "It is obvious that we have completed our task there."

He added that the Syrian army has continued to make advances against ISIS, even though Russia pulled out some of its warplanes from Syria last month. The Russian air campaign started on Sept. 30.

The fighting in Syria has killed nearly half a million people in 5 years, according to the Syrian Center for Policy Research.

Putin said it's essential to prevent the collapse of the Syrian state to stem the flow of refugees to Europe, The Associated Press reports.

Putin also hailed the cease-fire which started on Feb. 27, brokered by Moscow and Washington. However, ISIS and Syria's Al Qaeda branch known as the Nusra Front don't have to abide by the truce.

Shortly before Putin’s comments, a leader of the U.N.-backed humanitarian efforts for Syria said he was "disappointed" with recent efforts to get aid convoys into hard-to-reach and besieged areas, and called on the Damascus government to "live up to its promises."

Jan Egeland, the humanitarian aid adviser for the U.N.'s Syria envoy, told reporters on Thursday in Geneva that "April was supposed to be our best month" but that aid delivery is "not getting better and better, it's actually slowing down."

Egeland spoke during a break in U.N.-sponsored indirect talks between the Syrian government and the opposition delegation, which are to resume next week.

The Associated Press contributed to this report.