San Francisco, Feb 13 : Amazon's use of an app called "Mentor" to track third party delivery drivers and measure their performance has triggered privacy concerns, according to media reports. While Amazon calls the app a tool to improve safety of drivers, privacy proponents and drivers say that it is also a tool for surveillance, CNBC reported on Friday. The app helps Amazon to monitor the behaviour of the drivers while on delivery service. The delivery drivers are required to download and continuously run it. It gives them a score that measures their driving performance. However, some delivery drivers, cited by CNBC, find the app invasive and said that they at times face unfair disciplinary action from their manager due to bugs within the app. "Safety is Amazon's top priority. Whether it's state-of-the art telemetrics and advanced safety technology in last-mile vans, driver-safety training programs, or continuous improvements within our mapping and routing technology, we have invested tens of millions of dollars in safety mechanisms across our network, and regularly communicate safety best practices to drivers," an Amazon spokesperson was quoted as saying. These concerns come at a time when Amazon earlier this month raised eyebrows by confirming that it is introducing always-on cameras in vans used by some of its contracted delivery partners, causing alarm among privacy advocates. /IANS