LONDON (AP) — Air travelers faced possible delays at U.K. airports Friday as government employees who check passports went on strike in the latest of a spate of walkouts over pay amid a cost-of-living crisis.

France braced for similar Christmas travel disruption, with a weekend rail strike starting to bite on Friday.

The strike by Border Force staff was due to continue through the end of the year, with the exception of next Tuesday.

Hundreds of thousands of passengers could be affected, though the British government said it was preparing military personnel and workers from other public services to help out at airports.

The strikes are putting pressure on Prime Minister Rishi Sunak's Conservative government, which is refusing demands from public sector workers for substantial pay rises.

Inflation stood at 10.7% in November, driven by food and energy prices in the wake of the COVID-19 pandemic and Russia's invasion of Ukraine.

Sunak said he regretted the walkout and advised people to check on their journey plans before setting out.

"I am really sad and I am disappointed about the disruption that is being caused to so many people's lives, particularly at Christmas time," he said during a visit to a homeless shelter in London.

He insisted his government has acted "fairly and reasonably" in public sector pay negotiations.

Thousands of National Health Service nurses walked off the job Tuesday in their second 24-hour strike this month. Ambulance drivers, paramedics and dispatchers also went on strike earlier this week and plan another walkout on Dec. 28.

Postal deliveries, highway maintenance and driving tests are also being disrupted by strikes.

Further travel difficulties loomed on Saturday, Christmas Eve, when most train services were expected to be canceled.

The labor unrest is set to continue into the new year, when more strikes are planned.

Nurses announced Friday they plan walkouts on Jan. 18 and 19.

France faced similar problems with travel and walkouts.

About half of France's train conductors are going on strike for the Christmas weekend. A third of scheduled train services were canceled Friday and 40% of trains were canceled for Saturday and Sunday, according to the SNCF national rail authority.

The strikers are demanding higher pay and more staff. It's among several strikes in France stemming from the rising cost of living, including energy bills, in recent months.

High-speed train lines from France to Spain and Italy, and regional services, were also due to experience disruptions.

Conductors, who collect tickets and manage on-board operations, are demanding more than the 12% over two years offered by SNCF.

The strike came at a time of traditional gatherings for many French families who struggled to meet family and friends during the COVID-19 pandemic. Travelers expressed anger at the walkout, which was strongly criticized by the French government.

"To go on strike at such a time is incomprehensible and unjustifiable," French Transport Minister Clement Beaune told France Info.