Indian Prime Minister Narendra Modi's efforts to improve ties with Nepal have suffered a serious setback, analysts say.
A tough message from New Delhi telling its smaller neighbour to find a way to curb ongoing protests over its new Constitution has prompted accusations from Kathmandu of Indian interference in its politics.
Protests continued yesterday, however, in Nepal's Terai region bordering India. Ethnic groups like the Madhesis, who have links to India, are unhappy with the Constitution which they say divides their homeland in the south and gives them inadequate political representation.
The movement of trucks carrying goods and fuel tankers was disrupted by the protests, raising fears of food and fuel shortages in Nepal.
Spokesman Vikas Swarup for India's Ministry of External Affairs said in a statement yesterday that the "obstructions were due to unrest, protests and demonstrations on the Nepalese side".
Traditionally, India has exerted influence in Nepal, a land buffer between India and China. But it has also been criticised that it takes its neighbour for granted.
Mr Modi has made India's neighbours a foreign policy priority and has wooed Nepal since coming to power last year. In August this year, he offered a US$1 billion (S$1.4 billion) line of credit while on a visit there. When the earthquake struck in April, he personally stepped in to mobilise rescue missions.
But this last week, ties took a nosedive over India's lukewarm reaction to Nepal's new Constitution.
"Modi's successful visit has now evaporated," said South Asian analyst S.D. Muni. "From the kind of notes and statements that have been exchanged, it is very clear that the relationship has touched a new low."
Last week, India sent Foreign Secretary S. Jaishankar to Kathmandu to urge it to work for a political consensus before adopting the new Constitution. Since that failed, India has issued almost daily statements urging Nepal to find a political solution.
Yesterday, it urged Kathmandu to deal with "the causes underlying the present state of confrontation credibly and effectively".
Critics said India's response was too strong, triggering a backlash in Nepal. "No way can the Indian response be justified," said Nepalese political analyst and journalist Kanak Mani Dixit. "Nepal's Constitution is written by a constituent assembly and endorsed by elected by members from all regions."
India shares an open border with Nepal, meaning the countries' citizens do not need visas to travel across the border, raising fears that the protests in the Terai region could spill over into the neighbouring Indian state of Bihar, which is gearing up for polls soon.
Against this backdrop, some feel the tough message was warranted.
"India was giving a frank message," said former Indian ambassador to Nepal P.V. Rajan.
"Sometimes, you have to bypass diplomatic niceties and be very frank. If it had postponed its reaction, the problems would have become more. Now, corrective trends have started. The Prime Minister (of Nepal) has cancelled his visit to the UN to deal with the crisis and hold talks (with the ethnic groups)."