By Daniel Burke, CNN Belief Blog Co-Editor

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(CNN) - The Transportation Security Agency has issued an advisory about the Muslim holy month of Ramadan, telling its workforce and passengers that they may observe Muslims fasting, carrying prayer beads and whispering prayers on planes and in airports.

Ramadan begins this week, though the exact date varies depending on locale. It is the holiest month of the year for the world's 1.5 billion Muslims, during which many fast during daylight hours and dedicate more time than usual to praying and reading the Quran.

"Whenever the TSA is trying to create an environment of understanding, we welcome that," said Haris Tarin, director of the Muslim Public Affairs Council's Washington office. "At the same time, it highlights certain actions that can make the American Muslim population seem almost alien."

In a statement issued July 2, the TSA said it has "reminded its security workforce that traveling passengers may be observed at various areas in the airport - including security checkpoints or on aircraft - engaged in religious practices and meditations during Ramadan."

READ MORE: The Belief Blog Guide to Ramadan

The public, as well, should know that they might see Muslims observing Ramadan rituals at airports, the TSA said.

Those activities may include: abstaining from food and water; praying on airplanes and at airports; ritual ablutions in airport bathrooms; reading or reciting the Quran, the Muslim holy book; carrying prayer beads and whispering "prayers constantly."

A TSA spokesman said the agency issued similar Ramadan advisories in 2011 and 2012 and has also issued memos on Jewish holidays.

The TSA advisory seems designed to pre-empt problems Muslim-American travelers have experienced since the attacks of September 11, 2001 - a phenomenon sometimes satirically referred to as "flying while Muslim."

"I've consistently faced 'random' selections for extra screening at the airport after I decided to wear the hijab, or Muslim head covering," Nafees A. Syed wrote in a 2010 piece for CNN. "I've been told to take my head scarf off or have my head probed while the passengers in front of me offered pitying smiles as they rushed to their flights."

Other Muslims have been removed from flights after being seen praying at the gate area and saying "Allah" - God in Arabic.