TRIPOLI, THE LEBANON'S SECOND CITY. IS UNDER COMPLETE CURFEW TODAY, AFTER A WEEK OF VIOLENT DISTURBANCES.

THE TROUBLE HAS ARISEN FROM THE LEBANON GOVERNMENT'S ATTEMPT TO CURB THE OPERATIONS OF PALESTINIAN COMMANDO UNITS OPERATING IN SOUTH LEBANON, CLOSE TO THE ISRAELI BORDER.

GOVERNMENT TROOPS MOVED AGAINST THE COMMANDOES LAST WEEK. THEIR ACTION SPARKED OFF A POLITICAL CRISIS AND BROUGHT ANGRY PROTESTS FROM OTHER ARAB STATES.

TO THE EAST, SYRIA SENT TROOPS OVER THEIR BORDER WITH THE LEBANON TO LAY SIEGE TO A SMALL VILLAGE.

THERE HAVE BEEN CLASHES BETWEEN SECURITY FORCES AND SUPPORTERS OF THE COMMANDOS IN MANY PARTS OF THE COUNTRY. TRIPOLI IS ONE OF THE MAJOR CENTRES OF THESE DISTURBANCES. A TRADITIONAL TROUBLE SPOT BECAUSE OF THE STRONG LEFT-WING ELEMENT IN ITS POPULATION, AND THE PRESENCE OF A BIG PALESTINIAN REFUGEE CAMP, THE SITUATION THERE DETERIORATED RAPIDLY AFTER SECURITY FORCES FIRED ON DEMONSTRATING CROWDS ON FRIDAY.

COMMANDOS SUPPORTERS TOOK OVER THE OLD CITY AND OCCUPIED THE CRUSADER CASTLE YESTERDAY. THE AREA IS NOW RINGED BY GOVERNMENT TROOPS.

THOUGH THERE WAS SPORADIC GUNFIRE YESTERDAY, REPORTS TODAY SAY THAT THE SITUATION IS QUIET.