ISLAMABAD (AP) — Texters in Pakistan better start watching their language.

Pakistan’s telecommunications authority sent a letter ordering cell phone companies to block text messages containing what it perceives to be obscenities, Anjum Nida Rahman, a spokeswoman for Telenor Pakistan, said Friday.

It also sent a list of more than 1,500 English and Urdu words that were to be blocked.

The order was part of the regulator’s attempt to block spam messages, said Rahman. The Pakistan Telecommunication Authority refused to comment on the initiative.

Many of the words to be blocked were sexually explicit terms or swear words, according to a copy of the list obtained by The Associated Press.

It also included relatively mild terms like fart and idiot.

The reasons for blocking some words, including Jesus Christ, headlights and tampon, were less clear, raising questions about religious freedom and practicality. Any word could conceivably be part of a spam message.

The letter, which was also obtained by the AP, was dated Nov. 14 and gave cell phone companies seven days to implement the order.

Rahman, the Telenor spokeswoman, said her company first received the letter Thursday and was discussing how to proceed.

“It’s a big issue, so it is being examined carefully from all points of view,” said Rahman.