NAIROBI, Jan. 24 (Xinhua) -- Somalian Al-Shabaab militants who kidnapped two Kenyan civil servants a year ago have threatened to kill them unless Kenya releases all Muslim prisoners held on terrorism charges.
In a statement posted on the militants' Twitter account Wednesday night, the Al-Qaida-allied group gave Kenya, which launched a military campaign in southern Somalia in October 2011 to pursue militants blamed for insecurity in the country, three weeks to release the prisoners.
"The Kenyan government must release all Muslim prisoners held on so-called terrorism charges in Kenya. The Kenyan government must secure the release of Muslims extradited to Uganda for terrorism charges," Al-Shabaab said in the message.
The insurgents have also released a video of the two Kenyans, who were seized from the frontier county of Wajir, claiming "the video carries an important message from the prisoners, and Kenyan government is advised to pay close attention to the pleas of the POWs (prisoners of war)."
"The release of the Muslim prisoners is unconditional and must be made public," it posted on Twitter.
"Kenyan government has three weeks, starting midnight 24/01/2013 to respond to the demands of HSM (Harakat Al-Shabaab Al-Mujahideen) if the prisoners are to remain alive," it warned.
"Following the expiration of this period, all the Kuffar Kenyan prisoners who appeared in the recent video will be executed," Al-Shabaab said.
The threats came barely a week after the militants executed French intelligence agent Denis Allex in retaliation for a botched French operation to free him.
Kenya has heightened security around the country, with security agencies at an unprecedented state of alert after recent reports Al-Shabaab planned attacks against the East African nation and foreign interests in the country.
The militant group has also come under pressure from African Union peacekeepers, which have pushed them out of the Somali capital Mogadishu and from Ethiopia.
Al-Shabaab is known for enforcing a strict brand of Islam in the areas under its rule and is believed to have links to Al-Qaeda. The group has also blocked some international aid workers from accessing parts of Somalia suffering from drought and famine.
Kenya blames the group for a string of attacks and kidnappings on its territory, including those of four Europeans.
The Kenyan government says the kidnappings threaten tourism, a key source of revenue for the country.
Al-Shabaab has been fighting since 2008 to topple Somalia's weak central government. It is considered a terrorist organization by the U.S. government.