NAIROBI (Reuters) - Kenya's two biggest telecoms operators, Safaricom and the local unit of Bharti Airtel, have made a joint bid for the smallest operator, Indian group Essar Coomunications' Yu, the industry regulator said on Monday. The Communications Commission of Kenya (CCK) said it had received applications from the firms to allow the transaction that will see Safaricom and Airtel spend a combined $100 million. Local newspaper reports said Safaricom, which is 40 percent owned by Vodafone, will get Yu's infrastructure such as base stations in a bid to improve the quality of its network. Meanwhile Airtel is expected to acquire the subscriber base that Yu has built up since entering the Kenyan market in 2008, said The Sunday Nation newspaper. Bob Collymore, the chief executive of Safaricom, told Reuters they would make a formal announcement when the deal is finalised.