Islamabad, Pakistan (CNN) -- Cell phone carriers in Pakistan say they have been told to ban the use of about 1,500 words deemed indecent or offensive in text messages.
The notice from the Pakistan Telecommunication Authority (PTA) was received by three Pakistani cell phone carriers -- Mobilink, Warid and Telenor -- this week, officials at the companies confirmed.
The PTA calls for carriers to implement the ban, which would mean blocking text messages containing the offending words, within seven days of the notice, which was dated Monday.
Most of the banned words were deemed sexually explicit or obscene by the PTA, the officials said.
The words include "taxi" -- often used to refer to prostitutes in Pakistan -- "gay," "tongue," "homosexual," "intercourse," "condom" and "hole."
In the notice, the PTA -- the agency that regulates cell phone and internet carriers in Pakistan -- cited a law that bans the transmission of indecent and obscene messages.
The notice says the banned words are part of an effort to cut down on spam and unsolicited text messages, the officials said.
Omar Manzur, a spokesman for Mobilink, told CNN his firm is reviewing the notice, which it received Thursday, and plans to respond to the regulatory authority.
Last month, the PTA banned thousands of websites containing pornography.