By Yara Bayoumy

BEIRUT, Dec 6 (Reuters) The killing of a 21-year-old Shi'ite protester has opened up a new front in Lebanon's political crisis with rival media launching a war of words.

The West Asia country has six television channels mirroring party affiliations, but street protests by the Hezbollah-led opposition to bring down the Western-backed government have polarised broadcasters like never before.

Some fear the propaganda war could complicate efforts to end the political crisis.

Pro-government Future Television and al-Manar television owned by the opposition Hezbollah leapt on the death of the Shi'ite protester on Sunday to promote their agendas.

Ahmed Mahmoud was shot dead by an unknown assailant in a Sunni neighbourhood on his way from a protest in Beirut and was immediately dubbed ''The martyr of National Unity'' by Manar.

''He was killed by the militias of authorities,'' said a newscaster on the Shi'ite channel, openly blaming the anti-Syrian ruling coalition.

A newscaster on the Sunni Muslim Future television channel brushed off the allegation.

''Everyone in Lebanon, the Arab and Islamic world knows which is the only Lebanese faction that owns a militia,'' he said, referring to the pro-Syrian Hezbollah group that engaged Israel in a 34-day war this year.

Thousands of opposition followers have been camping out near government offices since Friday, paralysing the commercial heart of Beirut, to force the resignation of Prime Minister Fouad Siniora's cabinet which they say is a puppet of Washington.

Siniora's allies say the opposition is under the influence of Syria and a Sunni cleric hailed the prime minister on the Future channel today as ''the patient one''.

When the newscasters are not reading out party statements, the airwaves are filled with video clips designed to show the other side as the bad guys.

Future television airs soundbites by opposition politicians.

One clip includes a politician saying: ''We are proud of our relationship with Syria, we are proud of our relationship with Iran,'' and then cuts to a clip of Siniora saying: ''God guide them to the right path.'' Manar shows clips highlighting the government's ties with Washington, repeatedly showing footage of Siniora greeting US Secretary of State Condoleezza Rice.

Newspapers have warned that the television coverage risks inflaming passions in Beirut.

''The television war threatens to ignite the fire of strife,'' Al-Balad newspaper said in its front-page headline yesterday.

Siniora also seems aware of the dangers.

''A person who sits in front of the television will see that there is a daily and nightly campaign to exacerbate sectarianism,'' he said today.

Reuters BDP RS2248