GHAZNI, Afghanistan (Reuters) - The Taliban have warned Afghans that possessing pictures of “unrelated women and handsome boys” was against Islamic law and owning “shiny new phones” runs contrary to their religious dignity.

The Taliban have been posting “night letters” in the volatile southeastern province of Ghazni, reminding Afghans of their religious obligations and reiterating warnings that they will attempt to disrupt crucial presidential elections on Aug. 20.

In a restatement of the Taliban’s austere interpretation of Islam, one letter warned people, especially the young, against using hi-tech gadgets such as cell phones with photography and video functions.

“People with camera cellphones must not have pictures of unrelated women and handsome boys in their phones, which is against Islamic sharia,” reads one letter, obtained by Reuters on Monday. Sharia is Islamic religious law.

“People should think of their Afghan dignity rather than buying shiny phones,” it said.

Mobile telephones also should not have “immoral video clips”, ring tones with verses of the Koran, or derogatory messages against individuals or tribes. It regarded such offences as “a serious crime” that would be punished severely, the letter said.

The “night letters” have been springing up overnight in mosques and on the walls of Ghazni villages since last Friday.

The Taliban also warned voters in Ghazni to stay home from the day before the Aug. 20 election or face serious consequences.

With attacks escalating across Afghanistan in recent weeks, the Taliban’s leaders last week vowed to disrupt the poll, urging voters to boycott the ballot and “join the trenches of jihad”.

The letters in Ghazni have even been distributed by hand in one district, telling voters polling stations will be targeted.

“In order that this illegitimate process faces failure, the fighters will intensively attack polling centres, and (we) warn voters to stay home one day before,” read another letter.

The use of “night letters” and similar threats are a common tactic in the south and east, long Taliban strongholds.

WORSENING VIOLENCE

Attacks across Afghanistan this year had already reached their worst level since U.S.-led Afghan forces toppled the Taliban in 2001 and have risen further since U.S. and British troops launched offensives in southern Helmand last month.

The election, Afghanistan’s second direct vote since 2001, is consequently being fought against a backdrop of increased violence despite thousands of extra U.S. troops being poured into the country this year, in part to secure the poll.

The letters were distributed in Ghazni’s Qara Bagh district, the same area where Taliban insurgents ambushed a convoy of campaigners working for President Hamid Karzai on Saturday. One bodyguard was killed.

One district official, who asked not to be identified, said such letters could have a big influence on residents even though most cannot read or write. “People just obey the Taliban no matter what the letters say,” he said.

The Aug. 20 poll is seen as a critical test of U.S. President Barack Obama’s new regional strategy to defeat the Taliban and secure Afghanistan, as well as of Kabul’s ability to stage credible and legitimate elections.