British authorities are taking provocative messages in an Al Qaeda-linked online magazine seriously and have warned that readers of the site may be prosecuted.

The latest edition of Inspire Magazine -- an English-language online magazine published by the Yemen-based Al Qaeda in the Arabian Peninsula -- is inciting its readers to attack public targets in the West.

Britain’s Metropolitan Police issued a warning that anyone reading the radical Islamist site could face prosecution and issued a formal advisory to other police forces, making them aware of the content of the publication’s spring 2014 issue.

The magazine urges jihadists to target heavily populated events such as political rallies and sporting events, both in the U.S. and abroad - including in the U.K., France and other "crusading" countries. Would-be bombers encourages attacks during “election seasons” and between Christmas and New Year’s Eve. Specific targets are also cited, including Chicago’s "Sears Tower" (now called the Willis Tower), military bases in northern Virginia and soccer stadiums in Great Britain, particularly during Premier League matches.

"The MPS Counter Terrorism Command is aware of the websites and appropriate steps have been put in place, including providing security advice where relevant,” a British police spokesman told Sky News.

"The public is reminded that viewing downloading or disseminating extremist material within the UK may constitute an offence under Section 1 and 2 of the Terrorism Act 2006," the unnamed spokesman added.

Editorial and technological flaws in the magazine have raised doubts about the publication's authenticity.

Inspire began publishing in 2010, and its first issue included a now infamous article titled "Make a bomb in the kitchen of your Mom" that instructed would-be jihadists to use materials commonly found in a household kitchen, including a pressure cooker.

A U.S. official told Fox News in April that Boston Marathon bombing suspect Dzhokhar Tsarnaev admitted to investigators that he and his brother Tamerlan learned how to build the bombs used in the marathon attack in April last year by reading the magazine.

Inspire’s spring issue comes nearly a year after the Boston Marathon bombing, and as the city readies new security measures for this year's race in April.

“My Muslim brother, before you start reading the instructions, remember that this type of operation, if prepared well and an appropriate target is chosen, and Allah decrees success for you, history will never forget it,” the magazine reads. “It will be recorded as a crushing defeat on the enemies of Islam,” the magazine reads.

The publication is believed to have been started by Samir Khan, a U.S. citizen who moved in 2009 from his family's home in North Carolina to Yemen, where he was later killed in a U.S. drone strike along with Al Qaeda leader Anwar al-Awlaki.

The magazine is released through online jihadist forums -- some of which are open, while others are password protected, according to terrorism researchers.

But one issue of Inspire encourages readers to seek out its information from non-jihadist websites, like blogs and even news outlets -- which publish the magazine's content -- so as not to attract the attention of law enforcement monitoring the forums, a counter-terrorism source previously told FoxNews.com.