The Latest on the Syrian conflict as a cease-fire enters its fifth day (all times local):

3.50 p.m.

The U.N. humanitarian agency says aid convoys to besieged areas of Syria are being delayed because of several issues of a "logistical nature."

Spokesman Jens Laerke of the U.N. Office for the Coordination of Humanitarian Affairs said Wednesday it is critical for the assistance to proceed but "we need a much simpler procedure."

As a U.S. and Russian-engineered cease-fire took hold in Syria, the U.N. said Monday it plans to deliver assistance to about 154,000 people over the next five days in Syria.

Some assistance entered the Damascus suburb of Moadamiyeh Monday but the rest of the aid has been held up. Laerke told AP in Geneva "it's a mixture of things" including "facilitation letters" that are still pending with the Syrian government

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3.30 p.m.

Syrian opposition activists and state media say a Kurdish-led fighting alliance has captured a hill overlooking a main road in Aleppo from the militant Nusra Front group and its allies, in a surprise offensive aimed at encircling the northern city.

The predominantly Kurdish U.S-backed Syrian Democratic Forces' offensive Wednesday mostly likely does not break the cease-fire that came into effect Friday, because Nusra Front and Islamic State group are excluded from the agreement.

Syrian troops and the SDF had halted their offensive in northern Syria for days after the cease-fire began.

Syrian state TV reported that pro-government gunmen captured Castello hill, "cutting supply lines for terrorists" in eastern neighborhoods of Aleppo with southern parts of the Aleppo province.

Sami al-Raj, an Aleppo-based opposition activist, confirmed via Skype the SDF advances.