Middle East live updates: IDF says Israelis entered Lebanon in 'serious incident'

In response to a question about the suspected mass graves being uncovered in Syria, State Department spokesperson Matthew Miller said Tuesday that the U.S. has evidence of other atrocities that occurred under toppled President Bashar Assad's regime that is not currently available to the public.

"When you look at the evidence that is coming out of Syria in the now 10 days since the Assad regime fell, it continues to shock the conscience," he said.

"And I'm referring not just to the mass graves that have been uncovered, but information that we have been gathering inside the United States government, including information that's not yet publicly known," Miller added.

"We just continue to see more and more evidence pile up of how brutal they were in mistreating their own people, in murdering and torturing their own people," Miller said.

-ABC News' Shannon K. Kingston

State Department spokesperson Matthew Miller told reporters Tuesday that "fairly intense diplomatic discussions" aimed at staving off renewed fighting between Turkey plus its allied militias and the Kurdish-led Syrian Democratic Forces in northern Syria were ongoing.

"We continue to engage with Turkey about the situation in northern Syria," Miller said. "As you know, we worked out a ceasefire for the area around Manbij. That ceasefire has been holding. It had expired. It has been extended until the end of this week, and we continue to engage with the SDF, with Turkey about a path forward," he said.

Although the U.S. is allied with the SDF, Miller described Turkey's concern about the terror threat posed by the Kurdistan Workers' Party -- a U.S.-designated terror group which Turkey claims is directly linked to the SDF -- as "very legitimate."

-ABC News' Shannon K. Kingston

At least 38 Palestinians were killed and more than 200 injured in the past 24 hours of Israeli strikes in Gaza, according to Palestinian Civil Defence authorities in the Hamas-run territory.

The Israel Defense Forces also issued a new evacuation order for Palestinians residing in the Bureij area in the center of the strip.

-ABC News' Diaa Ostaz and Joe Simonetti

The Israel Defense Forces told ABC News on Wednesday it "removed from the area" a group of alleged Israeli settlers that crossed into Lebanese territory.

"The preliminary investigation indicates that the civilians indeed crossed the blue line by a few meters and after being identified by IDF forces, they were removed from the area," the IDF said in a statemen.

"This is a serious incident that is being investigated," the IDF added. "Any attempt to approach or cross the border into Lebanese territory without coordination poses a life-threatening risk and interferes with the IDF's ability to operate in the area and carry out its mission."

The south of Lebanon remains under IDF evacuation orders following Israel's recent ground offensive there. Israeli forces have committed to withdrawing from all Lebanese territory within 60 days of a ceasefire that came into force on Nov. 27.

-ABC News' Anna Burd and Joe Simonetti