Amidst the row over allegations of EVMs not being tamper-proof, NCP chief Sharad Pawar has asked his party's booth-level workers to stay alert at the time of demonstration of voting machines on the polling day. Various opposition parties have alleged that the electronic voting machines (EVMs) can be tampered with, and they want the Election Commission (EC) to revert to the ballot paper system of voting. However, the EC has repeatedly asserted that the EVMs are tamper-proof and that they cannot be hacked or rigged. "The BJP cannot be trusted.\u00a0On the day of polling, you better visit the polling booth in the morning and see if the voting is taking place properly or not," Pawar said addressing the party workers from Beed district in Maharashtra through video-conferencing on Saturday. NCP state chief Jayant Patil also interacted with the party workers. Also read| Lok Sabha election 2019 schedule: Election Commission to announce poll dates\u00a0today Top leaders of various opposition parties met last month in New Delhi to discuss the issue of alleged tampering of EVMs and chart out their future course of action. The opposition parties have been claiming that only two-three countries across the world are using EVMs and the rest have reverted to the ballot paper system following complaints of malfunctioning of these voting machines. The Congress, while supporting the demand, has maintained that since the Lok Sabha polls are just around the corner, the EC should ensure counting of paper trail in 50 per cent booths across the country to ensure there is no doubt in the minds of voters.