All vehicle movement in Nigeria's north-eastern Borno state has been banned from Christmas eve to Sunday morning to prevent attacks by militant Islamists, the army has said.
The decision has led to thousands of people rushing to get to their destinations, correspondents say.
Neighbouring Yobe has barred vehicles from entering or leaving the state.
Boko Haram militants have targeted churches during previous festive seasons.
The group bombed the St Theresa Catholic Church in Madalla near the capital, Abuja, on Christmas Day 2011, killing at least 43 people.
On Christmas Eve 2010, at least 32 people were killed in bomb blasts targeting churches in central Plateau state, which straddles Nigeria's mainly Muslim north and the Christian south.'Fear of massive attacks'
Boko Haram's insurgency has been most intense in Borno, Yobe and Adamawa, the three states where a state of emergency was imposed last year to beat back the militants.
However, the group has stepped up attacks since then, seizing large swathes of territory in Borno and capturing hundreds of people, including women and children, during raids on towns and villages.
Army spokesman Colonel Sani Usman said security reports indicated that Boko Haram planned to launch "massive attacks" during the Christmas period in Borno, especially on the state capital Maiduguri.
In order to guarantee public safety, people would not be able to travel by road in Borno from 18:00 local time (19:00 GMT) on Wednesday to 07:00 on Sunday.
People providing essential services such as medical care would be exempted, Col Usmani said.
BBC Nigeria analyst Ibrahim Shehu Adamu says similar bans were imposed during previous Christian and Muslim festive seasons and most people heeded them by walking to religious services or the homes of relatives.
The move is aimed at preventing Boko Haram from transporting explosives in cars or using motorbikes to carry out hit-and-run raids, he says.
The less restrictive travel ban in Yobe is not surprising, as it has not been as badly affected as Borno by the insurgency, he adds.
Boko Haram launched its insurgency in Nigeria in 2009 to create an Islamic state.
At least 2,000 civilians have been killed by the group this year.
The kidnapping of more than 200 schoolgirls by Boko Haram in April from the town of Chibok in Borno sparked international outrage.