Prime Minister Manmohan Singh says the intricacy of attacks indicate Pakistani government link.
Security for reporters improved worldwide, but Pakistan remains one of the deadliest places for the profession in 2008.
The diplomatic row between India and Pakistan continues to deepen following the November terrorist attack as both countries send more troops to their borders.
Readers write about why India should not give up Kashmir to Pakistan.
The effort, launched on the main supply route to Afghanistan, has suspended supplies sent to US and NATO forces there.
China and Russia join calls to avoid brinksmanship.