Prime Minister Manmohan Singh today called on President A P J Abdul Kalam amid reports of a possible Cabinet expansion expected later this week.The two leaders also discussed the forthcoming monsoon session of Parliament and the bills likely to come up. The 30-minute meeting was described by Rashtrapati Bhawan officials as ‘‘routine’’ and part of the regular interaction between the two leaders.Singh is understood to have briefed President Kalam about the recent Ayodhya attack and the security situation.