NEW DELHI — Uncertainty shrouds the future of India’s relationship with Bangladesh, which flourished for 15 years under Prime Minister Sheikh Hasina, who on Monday was forced to resign and flee the country amid strong anti-government protests that have left hundreds dead and plunged the nation into political turmoil.

“[We] will naturally remain deeply concerned till law and order is visibly restored,” External Affairs Minister Subrahmanyam Jaishankar told parliament on Tuesday.

“Our border guard forces have also been instructed to be exceptionally alert in view of this complex situation,” he said, noting that it was still evolving.

Jaishankar described Bangladesh as “an important neighbor on which there has always been strong national consensus.”

The two South Asian nations share a border of over 4,000 kilometers, and New Delhi remains in constant touch with Dhaka. It has “repeatedly counseled restraint and urged that the situation be defused through dialogue,” the minister said.

There were an estimated 19,000 Indian nationals in Bangladesh, including 9,000 students, but most of the students returned home in July.

Jaishankar said the situation facing minorities, including Hindus, is also being monitored in the Muslim-majority neighbor following reports of attacks.

Hasina and her Awami League party have strong ties with New Delhi. Bangladesh is India’s biggest trading partner in South Asia, and she warmed relations by working to improve trade and connectivity, and clamping down on anti-India militants on her side of the border.

Successive Indian governments have backed Hasina despite concerns about her high-handedness, intolerance of dissent and arrests of opponents. She developed a strong rapport with Prime Minister Narendra Modi when he entered office in 2014, and had previously enjoyed — and still has — close relations with the powerful Gandhi family and its ruling Congress Party.

Pallab Bhattacharya, the former Dhaka correspondent for the Press Trust of India who now writes for The Daily Star in Bangladesh from New Delhi, said the relationship between the neighbors will change.

“It can’t be business as usual approach,” he told Nikkei Asia. “India has invested so much politically and economically in Bangladesh since 2009 but now it will be uncertain whether that momentum can be sustained because [the new] government could comprise elements who are not very disposed toward India.”

He pointed to “anti-India elements” close to the opposition Bangladesh Nationalist Party and the Islamist Jamaat-e-Islami party, which could favor improving ties with India’s arch-rival Pakistan. That might lead to greater Chinese involvement in Bangladesh given the friendly relations between Islamabad and Beijing.

“Anti-India rhetoric could be sharpening now as such sentiment is already picking up in Bangladesh,” Bhattarcharya said.

Bangladesh is dependent on India for many essentials, including wheat, sugar, rice, vegetables and fruit. The garment industry sources raw material, especially cotton, from its giant neighbor. India is also behind a lot of infrastructure projects in Bangladesh.

“The biggest casualty in this could be India’s rail and road connectivity projects,” Bhattacharya said. “Those projects had taken quite a big stride during Hasina’s regime.”

Prerna Gandhi, an associate fellow at Vivekananda International Foundation, a New Delhi think tank, said instability in Bangladesh could directly affect India’s periphery. Bangladesh shares borders with five Indian states: West Bengal, Assam, Meghalaya, Mizoram and Tripura.

Gandhi said Hasina had put India-Bangladesh ties on an upward trajectory, but targeting of the Hindu population had been a sore point in the bilateral relationship in recent times. “These fears have clearly escalated even more now,” she said.

“For Indian strategic community, the focus on rethinking India’s engagement with the neighborhood, especially security engagement, will assume larger priority going ahead,” said Gandhi. “Geographic and other strategic realities ensure [that] India will have to be engaged by even alleged antithetical administrations in South Asia — India cannot be ignored and its ability to shape regional developments remains strong.”

Yogesh Gupta, a former Indian ambassador and secretary in the Ministry of External Affairs, said that India “will extend its full cooperation and support to the government and people of Bangladesh” while keeping a close watch on the situation “to ensure that its security and other interests are not adversely affected.”

“India would like to maintain its friendly relations and multifaceted cooperation with Bangladesh,” he said, no matter what parties come to power.

Jaishankar did not reveal how long Hasina will stay in India, amid reports that she is seeking asylum in the U.K.

Bhattacharya said that even if Britain declines asylum, Hasina “can always continue to stay in India.”

After her father Sheikh Mujibur Rehman — Bangladesh’s founder — was assassinated in 1975, she spent six years in India before returning to Bangladesh to lead the Awami League.

“That was a much younger Hasina, but now she’s already 76,” said Bhattacharya. “I doubt whether there is a possibility of her return to Bangladesh … but you cannot rule out anything in politics.”