* Army says it will fire on any armed person on streets
* Brief clash in west Beirut kills one woman
BEIRUT, June 28 The Lebanese army said on Sunday it would open fire on any armed person appearing on the streets, after a brief clash between supporters of rival political factions in western Beirut killed one person.
Gunfire erupted in the Aicha Bakkar area when Sunni Muslim followers of anti-Syrian Saad al-Hariri's Future movement clashed with supporters of the pro-Syrian Amal Movement, which is led by Shi'ite parliament speaker Nabih Berri.
Security sources said one woman was killed, and two people were wounded.
"This is an isolated incident between the groups' supporters on the back of the elections in Lebanon. The groups' leadership have nothing to do with it," a security source told Reuters.
Earlier this month, the U.S.-backed "March 14" coalition led by Hariri defeated Iranian-backed Hezbollah and its allies, including Amal, in a parliamentary election.
Heavy gunfire and celebratory firecrackers erupted after parliament elected Berri as speaker on Thursday and after Hariri was named Prime Minister-designate on Saturday.
"Orders have been given to (the army) to open fire on any armed person appearing on the streets and it will not tolerate any breach of security," a statement from the army leadership said.
Sunni-Shi'ite tensions threatened to boil over into a civil war last year when Sh'ite Hezbollah fighters routed supporters of Hariri and his allies in Beirut and mountains to the east.
A Qatari-mediated deal defused the crisis, but sectarian tensions rose again in the run-up to the election. Hariri is due to begin consultations on Monday to try to achieve his pledge of forming a national unity government. (Writing by Yara Bayoumy, editing by Mark Trevelyan)