Philadelphia police are searching for the men who stole 43 propane tanks from industrial yards in Northeast Philadelphia over the last two weeks.

The men have targeted two sites in the area since Dec. 17 - a construction yard on the 4700 block of Pennypack Street and another business on the 2300 block of Church Street, said Lt. Dennis Rosenbaum.

Rosenbaum said his unit had alerted the department's Homeland Security unit about the incidents, given the number of tanks taken and the capacity of some, "out of an abundance of caution."

"We want to make sure it's nothing sinister," he said. "Right now, we're treating them as industrial thefts, unless we come up with something else."

The Church Street property, he said, has been hit twice, once on Dec. 17 and once on Monday. Police did not say how many of the tanks were filled with propane.

Video at the Church Street location captured two men pulling up to the facility's fence around 10 p.m. Dec. 17 in a light-colored Ford Escape from around 2010 and a late-1990s Dodge or Chrysler minivan.

Rosenbaum said the men jumped the fence and then cut holes in it, through which they were seen pulling several propane tanks. Some of the tanks had the capacity to hold up to 100 pounds of propane, he said.

No video footage was recovered from the Pennypack Street property, Rosenbaum said, but the thieves employed similar methods there, cutting fences and locks to steal several tanks.

He said thefts of such size are unusual in the area - typically, propane tanks get stolen in more rural areas where propane tanks can be used to heat houses and trailers.

Rosenbaum said that anyone who notices anything suspicious, or has any information about the thefts, should call the department's anonymous tip line at 215-686-TIPS.