Cesar Villanueva Arevalo was sworn in as new Peruvian Prime Minister here Thursday at a ceremony held in the government palace, amid a cabinet reshuffle by President Ollanta Humala. Villanueva, 67, replaced Juan Jimenez, who resigned on Tuesday following a series of criticism from the opposition. He used to be the president of the northern San Martin region and is the fourth prime minister to serve in Humala's government. Villanueva said that he was assuming his new post with "much optimism", local radio station Radio Programas de Peru (RPP) quoted him as saying. He was named the prime minister at a time when citizen security is regarded as one of the government's priorities, the RPP said. Villanueva pledged on Thursday to strengthen security and work hard to boost the economy, saying he was willing to dialogue with the country's different political camps to ensure growth, local media reported. "There is no possibility of growing with the confidence needed without security. It will be a topic of permanent concern, and what we need is to mobilize all our efforts," Villanueva was quoted by local media as saying. The Peruvian president also swore in the new education minister while ratifying another 16 cabinet members at the same ceremony. The new appointment of a cabinet chief is seen as a measure to boost confidence in Humala's government, whose popularity has been slipping, reports said.