Indian and Japanese officials continued to wrangle over the legality of a document signed as part of the nuclear deal during Prime Minister Narendra Modi’s visit to Tokyo last week.

The document indicates a link between nuclear testing and the cancellation of the deal. While government sources say the document is “not legally binding,” a Japanese official insisted the document had been signed by the nuclear negotiators in the presence of Prime Ministers Shinzo Abe and Narendra Modi, and hence “legally binding.”

The ‘Note on Views and Understanding’ which was signed directly after the nuclear cooperation agreement contains contentious clauses that effectively allow Japan to invoke an “emergency” suspension of supplies if India were to test a nuclear weapon, and to contest any compensation claims from India in court. India has traditionally refused to link its nuclear trade with pre-conditions on testing, holding it is a matter of nuclear sovereignty, and instead giving a voluntary moratorium on tests.

In response to questions about the differences, government sources said the note is simply a “record by the negotiators of respective views on certain issues,” given “Japan’s special sensitivities as the only nation to have suffered a nuclear attack.”

Officials also explained that it had been included to help the Japanese government clear the deal in early 2017 through the Parliament or Diet, where it is already under fire for making an exception for India that has not signed the Non-Proliferation Treaty (NPT). “No, repeat no, additional commitments have been made by India,” the sources insisted.

However, when contacted by The Hindu, a Japanese government official was equally emphatic that their understanding was that the clauses contained in the note were views shared by both sides, and not individual views.

“It is signed by Amandeep Singh Gill and the Japanese counterpart official, and is legally binding as article II (on page 2) of the Note says ‘It is understood the above constitutes an accurate reflection of the views of the two sides’”, the official said.

“It is clear from Article 14 that Japan has the right to terminate its cooperation and other engagements stipulated under the Treaty. It has also been clearly confirmed between the two governments that Japan could do this in case India conducts a nuclear test,” he added. The Japanese official, who was privy to the negotiations also differed from the MEA’s reasoning for adding the note as an exception for Japan. “It is commonly practised among nations that they produce a separate document to record the understanding concerning their treaty implementation,” he said.

The wrangling over the Indo-Japan deal, which was hailed as a landmark agreement on Friday, casts a shadow similar to the controversy over the Indo-U.S. nuclear deal in January 2015.

At the time, despite Prime Minister Modi and President Obama announcing a breakthrough in negotiations on civil nuclear liability, U.S. companies refused to accept the Indian government’s assurances on limited liability, until months of discussions between the two sides convinced Westinghouse to go ahead with a plan for six nuclear reactors in Andhra Pradesh.

However, those reactors, and several others on the anvil, now await clearance of the deal with Japan, that has run into rough weather over the legality of the additional text.