MOGADISHU, Sept 21, 2006 (AFP) - Somalia's powerful Islamist movement flexed its muscles Thursday, announcing it was tightening Sharia law on its territory and vowing to fight the proposed deployment of foreign peacekeepers.

In a series of edicts, statements and court rulings issued just days after a failed attempt to assassinate the president of the country's weak transitional government, the Supreme Islamic Council of Somalia (SICS) moved to strengthen its grip on power.

Already in control of the capital Mogadishu and much of southern Somalia, the Islamists said they would seize the port of Kismayo and close the nation's border with Kenya to prevent an east African peacekeeping force entering the country to shore up the government's limited authority.

They also sentenced two alleged murderers to be executed in public, arrested a male martial arts coach and six female students, and banned the sale and use of the popular stimulant khat during the upcoming Muslim holy month of Ramadan.

Sheikh Mohamed Nur Duale, a top SICS member in the Lower Juba Valley, said the Islamists had surrounded Kismayo, about 500 kilometers (310 miles) south of Mogadishu, and would soon take it from a local militia.

"We will not attack our Muslim brothers in Kismayo or any other place in the region. Our objective is to defend the country from the enemies of Allah," he told AFP. "No one should dare stand in front of this holy objective."

Kismayo is currently held by the Juba Valley Alliance, a militia led by the defense minister in the government. But it has been encircled for several days by Muslim forces, who are negotiating what they say will be a peaceful handover.

Duale said the Islamists were intent on taking Kismayo because African Union-backed plans for the regional peacekeeping mission called for troops to land there.

Meanwhile, witnesses and Muslim militia commanders said the Islamists had boosted their presence along Somalia's remote and largely unpatrolled frontier with Kenya, where the vanguard of the 8,000-strong peacekeeping force from the seven-nation Inter-Govermental Authority on Development is to gather.

"We will close our border with Kenya before foreign troops can set foot on our soil," said one commander from the town of Dhobley, close to the Kenyan border.

The IGAD mission faces numerous hurdles apart from fierce Islamist opposition, not least of which is its cost, which neither the cash-strapped African Union nor the regional bloc can afford.

Yet, it has pushed ahead with the plans in order to salvage the Somali government it helped create two years ago in a bid to restore stability to a country that has been wracked by anarchy for the past 16 years.

But already crippled by fractious infighting, the administration has been unable to assert control and the Islamists have moved in to fill the power vacuum, sparking fears of a Taliban-style takeover of Somalia.

On Thursday, an Islamic court sentenced two men to be executed in public in Mogadishu on Friday after convicting them of killing a businessman while attempting to steal his cell phone, officials said.

"We are encouraging this practice to stop illegal killings in the country," said SICS security chief Sheikh Yusuf Mohamed Siad.

SICS Sharia law enforcers also arrested a karate instructor and six female students at a training facility in Mogadishu, alleging they had violated Koranic precepts on the mixing of the sexes and dress, officials said.

"The detainees were involved in un-Islamic behavior," said Sheikh Kadar Abdirahman Keyse, who runs the Islamic court in the capital's southern Hamarweine district.

In addition, the Islamists ordered ban on the daytime sale or consumption of khat and the closure of all restaurants beginning Saturday, when Ramadan begins.

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