By Geeta Pandey
BBC News, Delhi
The fire engulfed two carriages on the Samjhauta Express
India and Pakistan have reacted cautiously to the bombing of the Samjhauta (Friendship) express train - unlike in the past when similar attacks have resulted in a full-fledged war of words.
"This is an attempt to derail the improving relationship between India and Pakistan," said Indian Railways Minister Laloo Prasad Yadav.
His words were echoed in Islamabad by Pakistan's Foreign Minister Khurshid Ahmed Kasuri.
"This is very indicative of the minds of those who have done it. The governments of India and Pakistan would not, or should not, allow the perpetrators of this incident to derail the peace talks," Mr Kasuri said.
He advised the two countries against "hasty conclusions" and added that they "should hasten the peace process".
Mr Kasuri is due in India on Tuesday for four days of talks with Indian officials and a lot is at stake here.
The talks are meant to carry forward the peace process between the two neighbours which slowed down after last July's serial blasts on the rail network of India's financial capital, Mumbai (Bombay).
A scheduled meeting between the foreign secretaries of the two countries was put off. India said it was still committed to the peace process, but that bombings had made it difficult to carry on talking.
Although for the first few days, there was no finger-pointing, Mumbai police later blamed the bombings on Pakistan's ISI intelligence agency.
The peace process resumed after Indian and Pakistani leaders met in Havana
Islamabad rejected the allegation and demanded proof from India.
But the verbal exchange was not allowed to slide into a full-fledged war of words.
Indian Prime Minister Manmohan Singh and Pakistan's President Pervez Musharraf met in Havana in September on the sidelines of the Non-Aligned Movement summit and agreed to continue with the talks.
And the peace process got a new lease of life.
Pakistan's Foreign Secretary Riaz Mohammad Khan came calling in November and Indian Foreign Minister Pranab Mukherjee visited Islamabad in January.
Mr Kasuri's visit this week was expected to take the peace process another step forward.
It is obvious the governments on both sides do not want to derail peace moves.
"We must deny the terrorists any opportunity to sabotage the peace process," Mr Kasuri said.
India, too, responded in measured tones.
Without blaming anyone for the blasts, Prime Minister Singh said "the culprits will be punished".
Former foreign secretary SK Singh says: "Looking ahead, I can say both countries will carry on talking and take the peace process forward.
Relations with Pakistan have been strained since the Mumbai train blasts
"In the absence of any specific information," he says, "it's not right to point fingers at anyone or say who could be behind the attack."
But some analysts are willing to hazard a guess.
Former Indian high commissioner in Pakistan G Parthasarthy says: "It is a terrorist act."
He blames Pakistan-based Islamic militant group Lashkar-e-Toiba "or similar elements" for the attack.
"President Musharraf is not exerting enough pressure on these groups and until that happens, terrorist acts in India and Afghanistan will not stop," he says.
'Alive and kicking'
Against such a backdrop, some are saying the talks are meaningless.
Former Indian high commissioner to Pakistan, Satish Chandra, says: "The infrastructure of terrorism is alive and kicking in Pakistan. Terrorism continues to remain an integral part of their foreign policy."
Mr Chandra says by carrying on talking to Pakistan, India is displaying an "approach that is extremely weak-kneed".
"The government says it will continue with the talks. The Indian government's unreal love-fest with Pakistan continues. The talks will only embolden the terrorists from carrying out more such attacks," he says.
Even though the attack on the Samjhauta Express took place on Indian territory, most of those killed in the bombings appear to have been Pakistanis.
In Islamabad, foreign ministry spokesman Tasnim Aslam demanded that India investigate the incident immediately. "We expect the Indian authorities to punish the perpetrators," she said.
Mr Chandra agrees - but he says it is Pakistan-based militant groups who have carried out the attack.
"Look at the number of terror incidents in Pakistan. Many people are killed routinely. Terrorists are not bothered about who they are killing. They have achieved their purpose. Now it's for Pakistan to take steps," he says.
Considering that both sides suffered losses in the attack, some say it may well be the catalyst needed to make the two countries join hands and work together.
Senior Pakistan-based journalist Marianna Babar says the attack on the Samjhauta Express shows how large the terrorists' network is.
"It's the first big challenge for the joint mechanism on terror which India and Pakistan formed after the Havana meeting," she says.
How the two countries deal with this challenge will be an indication of whether the future will be as tense as the present.