After a quiet two weeks on Yale’s campus, two graduate students were robbed within two blocks of the Yale Security headquarters on Howe Street Saturday, and a postdoctoral fellow was assaulted Monday afternoon.

Yale Police Department officers said the Saturday robberies, which took place within hours of each other on or off Dwight Street, were unrelated. Still, they advised students to exercise vigilance in the area. The police department has raised the number of both uniformed and undercover officers in the Dwight neighborhood, said Associate Vice President for Administration Janet Lindner.

Yet despite the recent robberies, four people interviewed in the neighborhood said they felt generally safe in the area, which is home to hundreds of Yale students living off campus.

Suleiman Chater, manager of Mamoun’s Falafel on Howe Street — located less than a block from the first robbery — said he thinks the area is safe because of the combination of multiple cameras and the Yale Security headquarters on his street. He added that he has not noticed a drop in clientele after any recent crime incidents.

Police patrols will also increase around Edwards and Prospect Streets on Science Hill after the attempted robbery of a postdoctoral fellow in the area around 4.30 p.m. Monday, Yale Police Department Chief Ronnell Higgins said in an email to the Yale community. Five males aged between 15 and 20 approached the victim and displayed “what appeared to be a toy handgun,” striking the victim and unsuccessfully trying to make off with his backpack, Higgins said.

“As it gets dark earlier in the coming weeks, it’s especially important to be aware of your surroundings, to avoid walking alone, not display cash or other valuables such as phones or iPods, and use the security services Yale provides,” Lindner said.

Saturday’s two robberies, which Higgins communicated to the Yale community in two emails within three and a half hours, were the first criminal incidents reported to the campus this month. The department’s assistant chief, Steven Woznyck, did not responded to a request for comment Monday.

At 6 p.m. Saturday, a graduate student was robbed of her purse at 65 Edgewood Ave. — just two blocks from Pierson — by a male who “displayed a knife,” Higgins said in his email, adding the victim was not injured.

Three hours later, another graduate student was robbed less than three blocks from the first incident at 100 Dwight St. Two men stole the graduate student’s backpack and fled west along George Street, leaving the victim uninjured.

Because of the robberies, the Yale Police Department has increased patrols in the area around Dwight and Howe Streets, Lindner said in an email Monday.

In spite of the robberies, three students and one business proprietor in the area interviewed Monday said they felt safe on the blocks where the first two robberies took place.

Joseph Breen ’12, who lives off campus on the corner of Park Street and Edgewood Avenue, said he has noticed a police presence on the corner where he lives and outside Mamoun’s.

While Breen said the two robberies were “concerning,” he added that he has not sensed any greater danger recently.

“Crime is down this year on campus and in the community, continuing a trend of decreased crime for many years,” Lindner said. “But crime does exist here, as it does elsewhere, and city living requires a heightened awareness for certain crimes, particularly street robberies.”

On Sept. 29, the University released its annual crime report, which showed an 11 percent drop in the number of reported crimes during the 2009–’10 school year. However, 14 students were robbed in 2010 — the same number as in 2008.

Overall crime rates in the Elm City for the first half of 2011 are down about 9 percent from the same period in 2010.