0428 GMT May 21, 2019
Speaking at a news conference on Monday at the US State Department with German Foreign Minister Frank-Walter Steinmeier, Kerry said that teams in Geneva would look into reports of violations on both sides.
The top US diplomat added that he has agreed with his Russian counterpart Sergei Lavrov to intensify work on a mechanism to ensure that the strikes solely target the Daesh and al-Nusra Front terrorists.
"We are going to track down each alleged violation and work even more now to put in place a construct which will help us to guarantee that missions are indeed missions against Nusra or missions against Daesh," Kerry said.
The United Nations has confirmed that the ceasefire is largely holding in Syria, despite some reports of breaches.
However, Syrian Foreign Ministry has accused Saudi Arabia of attempting to thwart the truce. Russia has also accused Turkey of at least nine truce violations in Syria, including shelling in the northern province of Latakia.
The ceasefire agreed by the United States and Russia took effect in Syria on February 27 midnight Damascus time.
US Department of State spokesperson John Kirby said on Monday that Washington is aware of possible violations and that it is trying to get information from Russia in this regard.
"There have been reports of violations, however, and we take all such reports extremely seriously," Kirby stated. "With respect to airstrikes in areas where opposition groups taking part in the cessation of hostilities may be active, we are seeking further information, including directly from Russia."