BEIRUT (AP) — The Latest on Syria (all times local):

4:35 p.m.

The Russian military is questioning the conclusions by the international chemical weapons watchdog that victims of the April 4 suspected chemical attack in Syria were exposed to sarin or a similar toxin.

Defense Ministry spokesman Maj. Gen. Igor Konashenkov issued a statement Thursday questioning how the samples were collected and how the analysis could have been done so quickly. He said he would like to receive answers to these questions as soon as possible.

Konashenko said only by carrying out an objective investigation on the spot can the truth be established about what happened in the Khan Sheikhun area of Syria's southern Idlib province and who was responsible. The U.S. and many other nations have accused the Syrian government of responsibility.

Ahmet Uzumcu, director-general of the Organization for the Prohibition of Chemical Weapons, said Wednesday that the results "from four OPCW designated laboratories indicate exposure to sarin or a sarin-like substance."

3:10 p.m.

The U.N.'s chief humanitarian adviser for Syria says aid agencies have been able to reach fewer besieged people with relief this year compared to the same period last year.

Speaking to reporters in Geneva, Jan Egeland said the front lines have shifted but civilian suffering has "remained the same" in 2017.

Of nearly 5 million Syrians living in besieged or hard-to-reach areas, agencies have only been able to reach 564,000 this year, according to Egeland.

The Syrian government and rebels are allowing up to 30,000 people to leave areas besieged by their forces over the coming two months in a deal critics say amounts to demographic rearrangement. The U.N. is not supervising that deal.

Egeland said no Syrians should be forced out of their homes through starvation or siege.