No-one has claimed responsibility for Wednesday's attack and the initial police investigation has failed to unearth any clear leads on the blasts that also came ahead of a new round of India-Pakistan peace talks later this month.
|Pakistani spectators cheer during a daily ceremony to lower the flags of Pakistan and India at the Wagha border near Lahore on July 17, 2011.|
New Delhi has tried to avoid being seen to point the finger at its neighbour but India accuses Pakistan's army and intelligence services of aiding militant groups that have carried out attacks on Indian soil in the past.
For Clinton, any Pakistani involvement would again see her under pressure to drop US military support for Islamabad during her talks with Indian Prime Minister Manmohan Singh on Tuesday. She heads to Chennai the following day.
India, with whom the United States has been seeking a broader relationship, welcomed Washington's decision to suspend $800 million worth of aid to Pakistan.
"Counter-terrorism has always been part of our strategic dialogue," an Indian foreign ministry official told AFP ahead of the Clinton talks on condition of anonymity. "The July 13 attacks will be part of the exchange."
Clinton said last week that it was "more important than ever that we stand with India" and she reaffirmed her "commitment to the shared struggle against terrorism."
India broke off its peace process with Pakistan after the November 2008 attacks on Mumbai, which were blamed on the Pakistan-based group Lashkar-a-Taiba.
Ten gunmen went on a 60-hour rampage, killing 166 people across the city.
Robert Hathaway, director of the Asia programme at the Woodrow Wilson International Center for Scholars in Washington DC, said the latest attacks in Mumbai "will inevitably colour Secretary Clinton's visit."
He said the bloodshed in India's commercial capital had the potential to upset the delicate balance in the three US relationships in the region -- with India, Pakistan and Afghanistan.
"If it becomes clear that the Pakistanis at some levels were involved in these attacks, then it would certainly give greater force to Indian complaints that the United States has coddled Pakistan and is not being stern enough," he said.
"I think, as the Indians are to be commended for doing, we want to avoid jumping to a conclusion until we simply have more information into who is responsible for these deeds."
Clinton, who was in Athens on Sunday to offer support for the Greek government as it tries to tackle its perilous and worsening debt crisis, is scheduled to take in China, Hong Kong and Indonesia on her travels.