Russia’s recent movements near Syria’s city of Latakia suggest that Moscow plans to establish a “forward air operating base” there, the US has said.
Pentagon spokesman Jeff Davis said there had been a steady flow of people and equipment in the coastal area.
Russia says military equipment is being sent to Syria to help the government combat the so-called Islamic State.
Moscow has been a key ally of President Assad during Syria’s bloody civil war, which began in 2011.
“We have seen indications in recent days that Russia has moved people and things into the area around Latakia and the air base there that suggests that it intends to establish some sort of a forward air operating base,” Mr Davis said on Monday.
He added that the US was concerned that Russian military moves could come into conflict with US and coalition air strikes that were being conducted in Syria against IS.
US officials also fear that the stepped-up Russian support will fortify the regime of President Bashar al-Assad at a time when it has been losing on the battlefield and will complicate recent efforts to find a political solution to the conflict, the BBC’s Barbara Plett Usher in New York reports.
The US comments come just days after Syrian state media reported that two Russian cargo planes with 80 tonnes of humanitarian aid had landed in Syria.
The planes reportedly flew into an air base near Latakia – a stronghold of President Assad.
Russian Defence Ministry spokesman Maj Gen Igor Konashenkov said the plane was carrying materials for setting up a tent camp for refugees.
The Kremlin has dismissed any military build-up, although Foreign Minister Sergei Lavrov said last week that Russia would send more help to Syria if requested.
Freshman Noah Joyner, 18, said he stayed inside a bathroom in his dorm buildings during the lockdown.
“There were people banging on the doors to have somebody let them in,” he said. “It was pretty terrifying to hear people banging on the door.”
Police helicopters circled the campus and hundreds of officers swept the buildings.
Mr Lamb was apparently “easy going” and had taken some leave recently for “personal reasons”, Don Mitchell, an associate professor of English at the university, told Fox News.
He called Prof Schmidt “a gentleman in every sense of the word” and “a terrific family man”.
Roughly 3,500 students are enrolled at the university near the Arkansas border.
