Microsoft CEO Steve Ballmer arrived in Israel on Wednesday for a three-hour visit to inaugurate Microsoft's new research and development center in Herzliya. The ceremony was attended by President Shimon Peres and leading hi-tech representatives. "Microsoft is as much an Israeli company as an American company," Ballmer said, adding that the proportion of Microsoft employees per capita in Israel was similar to that in the United States. Over the past two years, Microsoft bought five companies in Israel, adding to its two R&D centers in Haifa, which employ a total of 600 people. The new R&D campus in Herzliya has two buildings stretching over 13,000 square meters. Over the next year, Microsoft plans to add another 150 employees, bringing its total number of R&D staff in Israel to 750. Ballmer praised the IT sector in Israel for being very advanced, and said Tel Aviv, as the birthplace of many start-ups, was a type of Silicon Valley. "I know very few places around the world that offer such a variety of start-up opportunities, and we intend to continue to invest in Israel," he said. Commentng on Microsoft's battle for Yahoo, Ballmer said the software giant was not looking to bid to buy all of Yahoo, but was in talks about other types of deals with the second-largest search engine, after Google. "We are not bidding to buy Yahoo," he said. "Yet, we are trying to have discussions about deals with Yahoo that might create value, but not a whole acquisition of the company."