A number of passengers on this week's landmark bus service between Indian and Pakistani-administered Kashmir have been given police protection.
Security is tight in Srinagar, Indian-controlled Kashmir
At least 10 travellers are staying in a heavily guarded tourist reception centre in Srinagar, in the Indian sector, amid security fears.
The service, which starts on Thursday, is seen as an important signal of improving India-Pakistan ties.
Militants opposing Indian rule have warned people not to travel on the bus.
Pakistan and India have fought two wars over Kashmir since independence in 1947.
Last week, a number of militant groups warned people not to use the bus service, saying they had a list of names of the initial passengers.
The passenger list has not been officially released for security reasons.
The bus will travel between Srinagar, summer capital of India's Jammu and Kashmir state, and Muzaffarabad, capital of Pakistan-administered Kashmir.
On Monday, a spokesman for the al-Mansurin group told the BBC the militants were not opposed to the re-union of divided families but that they should take a different route for the journey.
Militants accuse Pakistan of a climb-down in allowing the service, which they say undermines their campaign against Indian rule.
Police told journalists they would not be allowed into the tourist centre where the passengers are staying.
A dummy run for the bus service will leave Srinagar on Tuesday and travel to a police checkpoint on the Line of Control that separates the two sectors of Kashmir.
Last week, authorities in Indian-administered Kashmir declared the route for the bus service safe.
The deputy inspector general of police for north Kashmir, Raja Aijaz, ruled out any sabotage by militants.
The officer said there was round-the-clock surveillance on the road from Srinagar to the frontier district of Uri.
He said there were regular patrols and anti-sabotage checks along the road.
The bus link was announced in February after a meeting of the foreign ministers of India and Pakistan and is the latest move in a peace process that began at the start of last year.
The man chosen at the weekend to drive the bus on the Pakistani side has said he is proud to be helping families reunite.
Raja Pervez Khan, a driver for 16 years, will ferry his bus to the Line of Control where he will swap passengers with the bus from Srinagar.
"I never thought that I would be the one to drive a historic bus. It is because of Allah's grace that I have been chosen," Mr Khan told the Reuters agency.