A bus carrying international tourists who had been on a wine tour was stoned as it headed to the Cape Town International Airport at the weekend, View Africa Coach Charter said on Monday.The charter company's depot manager Pieter Uys said the bus driver was travelling from Franschhoek on the N2 on Saturday when the vehicle was targeted between the Airport Approach Road and Borcherds Quarry offramps."Some guys threw stones at the bus, breaking two windows and damaging side panels," Uys said."Our driver went on to the airport and the tourists got off in a hurry. No one was injured."It was not immediately clear what the motive was.ALSO READ: Nzimande, Oliphant fail to end bus strike as bosses hold firmHowever, Uys said some of the company's drivers were wary to enter certain "hotspots" since the start of a nationwide bus strike on April 18.When tourists had to be dropped off at the airport, drivers tried to use alternative routes, he said.Western Cape police spokesperson, Sergeant Noloyiso Rwexana, confirmed a case of malicious damage to property was opened but no arrest had yet been made.Tourists strandedLast Tuesday, a tour bus was attacked near the Castle of Good Hope in Cape Town, said Cape Town law enforcement spokesperson Wayne Dyason."Some of the strikers saw the bus and insisted that the driver join the strike," he said.A group hit the windows of the bus, took the keys from the driver and then threw them away."The tourists were stranded so law enforcement stepped in to transport them to their hotels."Elwierda coach charter company owner Wikus van Niekerk told News24 the company's buses were still operating at every depot across the country."At this stage we don't have any incidents."The bus strike is set to enter its third week on Wednesday.Employers' ultimatumOn Monday, South African Road Passenger Bargaining Council secretary general Gary Wilson said there were no negotiations at present."The unions are meeting in Johannesburg to decide how they move from here. The employers have made it very clear that they are not prepared to negotiate any further," he said."We are sitting at a very delicate point at the moment."Spokesperson for the South African Transport and Allied Workers' Union Zanele Sabela told Fin24 on Monday that employers had issued an ultimatum for unions to either accept a 9% increase or settle for a lower figure.Unions had initially demanded a 12% increase. Other issues which need to be addressed in negotiations include driver overtime and night shift allowances.Wilson said employers had since reverted to an offer of an 8% increase for the first year and an 8.5% increase for the second year, with the proposal to take other issues off the table and send the disputes to a task team for deliberation.Concern over prepaid ticketsThe strike has affected thousands of commuters.#Bustrike: 'You're lucky if you get in' - video shows insane overloaded taxiThe City of Cape Town said that its MyCiTi bus service remained suspended until further notice."Regretfully, this means that there will be no MyCiTi trunk or feeder services available for as long as the strike and lock-out continue," said transport mayoral committee member Brett Herron."The City wants to remind those commuters with monthly MyCiTi tickets that the monthly packages will be extended equal to the number of days that the strike action lasts. The number of days will be determined once the strike has come to an end."Go George bus service in the Garden Route said its passengers were also concerned about the one-month validity of their multi-journey tickets."It has been decided that the validity of tickets already purchased will be extended. Go George will confirm the length of the extension applicable," said manager James Robb.