On the eve of the first anniversary of the worst terror attacks in India, Pakistan finally took some action, filing charges against seven accused.

But in a message to country, Prime Minister Manmohan Singh reiterated that his Government "will not rest till the perpetrators of the Mumbai attacks have been brought to justice."

"We have taken up matter with the Government of Pakistan with all the force at our command. We expect masterminds of these attacks and their supporters to be tried and punished," he added.

The Prime Minister, who is on a visit to the US, said that he shares the grief of people who lost their relatives. "This is a day of remembrance and paying homage to innocent civilians and brave men in uniform, who lost their lives in one of the worst terror attacks India has seen," he said.

"26/11 was an attack to destabilize India's secular polity. The supreme sacrifice will not go in vain," he added.

"I wish to reassure the nation that strengthening internal security is our top priority, and we will leave no stone unturned to safeguard and protect the lives of our citizens," the Prime Minister said, adding, "India has taken several measures to strengthen security and intelligence systems. We will take more such steps till we are satisfied that we have fool-proof arrangements."