Several suspected al-Qaeda militants, disguised as fully veiled women, have reportedly been shot dead by Yemeni security forces near the Saudi border.
The militants were killed after one of them opened fire on a soldier who was checking their vehicle, officials say.
One report quoting a Yemeni official said three militants were killed - while another put the number at five.
The Yemeni offshoot of al-Qaeda has exploited recent instability to seize parts of the country's south and east.
Al-Qaeda in the Arabian Peninsula (AQAP) is regarded by the United States as the deadliest branch of the global jihadist network, blamed for several attempted attacks on Western targets.
The vehicle carrying the militants was stopped at a border crossing in the Hawdh area of northern Yemen, according to Yemeni security officials quoted by the Associated Press news agency.
One of the militants reportedly opened fire on a soldier who tried to enter the vehicle, lightly injuring him.
The agency quotes officials as saying that the soldier shot all three militants dead. The driver of the vehicle, who was also injured, is said to have confessed that he and his passengers were al-Qaeda members on a mission to attack Saudi border guards.
However, the AFP news agency quotes officials as saying that the vehicle had been carrying five al-Qaeda suspects, all of whom were wearing the niqab, a veil used by Yemeni women to cover their faces.
"As one of the soldiers climbed on board the bus for an inspection, one of the suspects opened fire and wounded him, prompting shooting from other soldiers at the checkpoint," a government official told the agency.
Al-Qaeda militants are active on both sides of the Yemeni-Saudi border. Six security officers were killed in an attack on a Yemeni border post in July.
Yemen has remained unstable since anti-government protests in 2011 forced the then-President Ali Abdallah Saleh from office.
In September, rebels from the Shia Houthi movement marched on the capital, Sanaa, clashing with fighters loyal to the main Sunni Islamist party.
Sporadic violence has continued in and around the capital since then, with the latest unrest centred on the district of Arhab, close to Sanaa's international airport.
Houthi fighters said they had taken control of the district on Saturday, after fighting in which at least a dozen people were killed.