India on Friday urged Pakistan to speak in one voice on the Mumbai terror attacks, with two ministers saying flip flops on the carnage were best avoided. "I am sure somebody else will refute him tomorrow," Home Minister P. Chidambaram said at a press conference here when asked to comment on Pakistani Navy chief Admiral Noman Bashir's statement that Ajmal Amir Kasab, the lone gunman captured during the Nov 26-29, 2008 carnage, and the nine other terrorists who had attacked Mumbai had not used the sea route to reach the port city. "Pakistan has often spoken in different voices (on the Mumbai carnage)," Minister of State for External Affairs Anand Sharma said at a press conference that preceded Chidambaram's. "This multiple speak, duplicity and denial has created confusion. They (the Pakistani leadership) have to decide to speak in one voice," Sharma maintained. "Once having accepted a fact, it is better to take that to its logical conclusion," Sharma added. Asked to comment on Bashir's statement that the Mumbai attacks pointed to the failure of the Indian Navy in maintaining vigil, Chidambaram said: "I don't need certificates or appreciation from the Pakistani Navy. "I have said in parliament there have been lapses and these will be plugged," the home minister added. Pakistan had earlier this month accepted that part of the Mumbai conspiracy had been planned on its soil. The country's Federal Investigation Agency has also registered cases against eight people, including Kasab who is in the custody of the Mumbai police, for their role in the terror attacks.