TEHRAN — An annual test of wills between Iran’s morality police and women who dress in ways that are deemed unacceptable has begun in cities across the Islamic republic.

But this year, the stakes are unusually high. As Iranian leaders attempt to deflect the public’s attention from economic woes spurred by crushing foreign sanctions, they risk alienating large segments of a society that is already deeply divided.

Mandatory female covering known as hijab has been a defining element of Iran since the Islamic Revolution in 1979. Although the laws regarding proper cover haven’t changed, some women have grown bolder in interpreting the limits of what they can wear, creating a conflict that inevitably flares each summer as temperatures climb.

The government’s offensive this year has been marked by the stationing of mixed-gender teams of morality police in Tehran’s main squares.

In recent weeks, 53 coffee shops and 87 restaurants have been closed in Tehran for serving customers with improper hijab or for other gender-related offenses, such as permitting women to smoke hookah pipes. Concerts have been abruptly canceled because of inappropriate dress and too much contact between male and female fans. Approximately 80 stands at an international food fair were closed last month because, officials said, the women working at them were either breaking hijab rules or wearing too much makeup.

Those arrested face up to two months in prison or even lashing, penalties that have been on the books for years but have rarely been imposed.

The aggressive enforcement and stiff penalties have spawned resentment.

“I felt disrespected and insulted,” said 30-year-old Sahar, who was arrested for wearing sleeves that went only to her forearms. “I’m a grown woman. I can decide what I can wear. I can make these decisions myself.”

But authorities have made the case this year that un-Islamic dress is a matter of national security and a symptom of longtime Western meddling in Iranian affairs. Officials routinely cite the improper wearing of hijab as the cause of a variety of social maladies, from women who marry later in life to those who go into prostitution. The root problem is often blamed on “foreign agents.”

Tehran’s police chief, Ahmad-Reza Radan, this month called support for improper hijab “part of the enemy’s soft war against us.”

In Iran and other Islamic countries, hijab, which means “cover” in Arabic, has come to define a type of dress code for women, the main priority of which is to obscure signs of femininity. In Iran, that has always meant covering women’s hair and much of the body. Traditionally, covering of the head, arms and legs has been strictly enforced. A long jacket, called a manteau, accompanied by a scarf, has been the accepted minimum.

Over the years, however, what passes as hijab has changed, and now a wide range of styles can be seen in any Iranian city — from the black, all-encompassing chador to brightly colored head scarves that barely stay in place.

Manteau and head scarf shops are some of the most successful retailers in Tehran, where women strive to incorporate fashion trends. Skinny jeans with flat shoes are in this year, and on the streets of Tehran, they are hidden in part by the long, loose-fitting manteaus that are all the rage.