Relations have been gradually warming between Pakistan and India, but the Mumbai bombings may have changed that, finds this Beeb analysis.

An excerpt:

For the first time since Tuesday's serial bombings in Mumbai, the Indian government has pointed a finger at its long-time rival.

Until now, Indian officials had been cautious in their comments - broadly describing the attacks as the work of terrorists but refusing to go any further.

But on Saturday, Delhi said that "no date had been set" for a meeting between foreign secretaries of the two countries that was scheduled to take place next week.

Indian Foreign Secretary Shyam Saran said that India was still committed to the peace process, but it had been made "more difficult" by the bombings.

Two Indian MPs have also cancelled their visit to a Commonwealth parliamentarians meeting in Islamabad.

These developments may be relatively small scale, but they nevertheless provide the first indication that the peace process is in jeopardy.

Militant cells

Off the record, some senior intelligence officials were more forthcoming, saying that Islamic groups with links to Pakistan were involved.

One report in an Indian newspaper on Friday even said that National Security Advisor MK Narayanan had briefed the cabinet on Thursday, saying there was little doubt on that score.

But now Prime Minister Manmohan Singh has publicly suggested that the blasts were carried out by militant cells supported from within Pakistan.

And yet Pakistan was one of the countries to condemn the bombing. So why is India being so pissy. Sanjoy Majumder as some theories:

With the investigation making little tangible progress, the Indian government is under increasing pressure to act and demonstrate that it is not a soft target.

Many people are angry that three days after the bombings, there appear to have been no significant arrests, nothing to indicate that the government was moving swiftly to crackdown on those responsible.

Other's believe that it is time India demonstrates it will not take things lying down, even if that means reading the riot act to its neighbour.

But there are serious doubts that even if groups in Pakistan were directly involved, that the country's leader General Pervez Musharraf can do much to confront them.

While some believe that at least a part of the Pakistani establishment is reluctant to act against militants fighting Indian rule in Kashmir, the reality is that the Pakistan government has little control over hardline Islamic groups largely based in the frontier tribal region along the Afghan border.