JERUSALEM

An attempt by Hamas police to detain a young woman walking with a man along the Gaza beach has raised alarms that the Islamic militant group is seeking to match its political control of the coastal territory with a strict enforcement of Islamic law.

The man she walked with and two of his peers were detained, beaten and ordered to sign statements promising not to engage in immoral activities, said the woman and one of the men.

The incident was the first known case of Hamas openly trying to punish a woman for behaving in a way it views as un-Islamic since seizing power two years ago. But it follows months of quiet pressure on Gaza's overwhelmingly conservative 1.4 million residents to abide by its strict religious mores.

Hamas officials in Gaza have publicly urged shopkeepers to take down foreign advertisements showing the shape of women's bodies and to stash away lingerie often displayed in windows. Officials search electronic shops to check if they are selling pornography on tiny flash drives.

Freelance journalist Asma al-Ghoul, 26, said she was spending time with a group of friends -- two women and three men -- on the northern Gaza shore.

Al-Ghoul swam, fully dressed, with a girlfriend, and then asked a male friend to walk her over to a nearby beach house rented by another couple she knew to shower and change.

Three male police officers showed up and waited for al-Ghoul in the beach house garden, said an eyewitness who asked to remain anonymous because of security concerns. They took her identity card and demanded she accompany them to a nearby station -- an order she refused.

An argument ensued and she was able to avoid detention and get her identity card back only after the homeowner contacted a senior Hamas official who intervened and spoke to the officers by telephone. The official, Taher Nunu, was not immediately available for comment.

However, al-Ghoul said her male friends were subsequently beaten by Hamas police.

Her story only became public after rights groups published excerpts on their websites.

Her version of events was confirmed by two other witnesses, including Adham Khalil, one of the men who was detained. Khalil said he was beaten.

Hamas police spokesperson Islam Shahwan denied the incident took place but said Gaza residents "must preserve our customs and Islamic traditions.''