Acting BSF Director General Daljit Singh Chawdhary and senior officials have arrived in Kolkata to review border security measures.

Reportedly, Hasina arrived in India in a C-130J military transport aircraft of the Bangladesh Air Force. Hours after she landed, National Security Adviser Ajit Doval met her, the PTI sources said.

Follow For LIVE Updates On Bangladesh Protests

The force has directed all its field commanders to be "on ground" and "deploy all personnel on border duty immediately", a senior officer told PTI.

The leaves of all the personnel posted along the Bangladesh border were cancelled in the last few weeks after Bangladesh witnessed massive protests and now all units have been asked to "acquire an all alert posture", he said.

A Delhi-based BSF spokesperson said the "situation on the Bangladesh border is normal as of now."

"Troops are aware and alert about the recent development and situation across the IB is being closely monitored to deal any unforeseen situation," he said.

A senior officer said that "leave of all personnel posted along the Bangladesh border was cancelled in the last few weeks after Bangladesh witnessed massive protests and now all units have been asked to acquire a high alert posture."

The BSF guards the Indian front on the eastern flank of the country that runs along five states.

West Bengal shares a total of 2,217 kilometres of border with Bangladesh, along with Tripura (856 km), Meghalaya (443 km), Assam (262 km) and Mizoram (318 km).

Security Beefed Up In Delhi

The Delhi Police has beefed up security at the Bangladesh High Commission in Delhi. Police have also tightened security outside the Indira Gandhi International Airport, in case Hasina lands in the national capital, an officer said.

"More barricades have been placed outside the commission and the number of police personnel deployed there has been increased," a Delhi Police officer said.

Several senior police officers, including New Delhi district's Deputy Commissioner of Police Devesh Kumar Mahla, visted the high commission to check the security arrangements, an informed source said.

Assam On High Alert

Following turmoil in Bangladesh, the Assam government on Monday issued "high alert" to all its districts sharing border with the neighbouring country, a senior official said.

Assam's Karimganj, Cachar, Dhubri and South Salmara-Mankachar districts share 267.5 km of international border with Bangladesh.

"We have alerted all the border districts to be on high alert. We have asked the District Commissioners and Superintendents of Police to personally monitor the border situation," the official told PTI.

The state government is keeping a close watch on the evolving situation

Meghalaya Imposes Night Curfew Along Border With Bangladesh

Meghalaya Deputy Chief Minister Prestone Tynsong on Monday said the state government has decided to impose a curfew along the international border with Bangladesh, amid the unrest in the neighbouring country.

The curfew along over 444 km of the boundary stretch will be applicable from 6 pm to 6 am daily until further notice, he said.

The decision was taken during an urgent meeting with Border Security Force (BSF) personnel and the Meghalaya Police.

"In view of the volatile situation, the state government has decided to impose night curfew along the international border with Bangladesh," Tynsong said.

PM Modi Chairs Meeting With Cabinet On Bangladesh Crisis

Prime Minister Narendra Modi chaired a meeting of the Cabinet Committee on Security on Monday night as the government's top brass was briefed about the situation in Bangladesh.

The meeting came as Bangladesh Prime Minister Sheikh Hasina fled her country and landed in India on her way to London.

Modi was joined by other members of the CCS, including Home Minister Amit Shah, Defence Minister Rajnath Singh, External Affairs Minister S Jaishankar and Finance Minister Nirmala Sitharaman.

They were briefed by officials on the situation in the neighbouring country, official sources said.

Bangladesh PM Sheikh Hasina Resigns, Flees Country

Bangladesh Prime Minister Sheikh Hasina on Monday resigned and left the country, several news reports said amid massive protests against her government that claimed more than 106 lives in the last two days.

The private Jamuna television news channel reported that Hasina was forced to quit as prime minister after massive protests against her government over a controversial quota system that reserved 30 per cent of government jobs for relatives of veterans who fought in Bangladesh's War of Independence in 1971.

The channel said that Hasina and her younger sister Sheikh Rehana left the country in a helicopter. Hours later, hundreds of protesters stormed the prime minister's official residence.

The government earlier ordered a complete internet shutdown as protestors asked the general public to join a "Long March to Dhaka". However, a government agency gave a verbal order to start broadband internet around 1:15 on Monday.

Hasina, the 76-year-old daughter of Bangladesh founder Sheikh Mujibur Rahman, had been ruling the strategically located South Asian nation since 2009. She was elected for a record fourth consecutive term and fifth overall term in the 12th general election held in January, amid a boycott by the main opposition party Bangladesh Nationalist Party (BNP) of former premier Khaleda Zia and its allies.

(With PTI inputs)