|Saleh, left, was found guilty of the October 11 bombings of an Aden sports centre that killed four people [Reuters]
Armed men have seized three soldiers a day after four other troops were also captured in the region in an apparent bid to pressure Sanaa into a prisoner exchange involving Southern Movement fighters.
Local officials said three soldiers had been snatched in Dalea on Sunday, while the other four had been abducted in al-Habilayn, and again Dalea, on Saturday.
The incidents took place after thousands of people had taken to the streets of Daleh to protest against a court ruling in nearby Aden on Saturday over the sentencing of Fares Abdullah Saleh to death.
Saleh was found guilty of the twin October 11 bombings of an Aden sports centre that left four people dead.
State media reported that Saleh carried out the bombing for a leader of the secessionist Southern Movement.
In Sunday's incident, the three soldiers, including an officer, were taken hostage at a checkpoint at the entrance to Daleh, said a local official. He said the captors were Southern Movement fighters.
The officer, Ahmed al-Ghithi, was travelling by taxi toward Aden when he was captured, said the official, speaking on condition of anonymity.
On Saturday, Taher Tammah, a Southern Movement official, said the abductions were to pressure the authorities to free prisoners who had been detained ahead of the Gulf Cup football tournament.
The November 22 to December 5 football contest was staged in the south of the country under tight security after the Southern Movement vowed to try to disrupt the tournament.
Tammah said the group seized the soldiers in Daleh and Lahij and "in exchange for their freedom demand the release of their colleagues arrested before the regional football tournament".
Speaking to Reuters on Sunday, Nasser al-Khubaggi, a leading member of the Southern Movement, said: "Those behind these kidnappings are armed citizens who are angry at the detention of their children and relatives in state prisons, among them the man sentenced to death on Saturday for the bombing of the sports club in Aden."
However, Khubaggi denied the movement itself was behind the kidnappings.
In a separate incident on Sunday, a security official said two soldiers were among four people wounded as armed men fired on a bus at the entrance to Daleh.
Local officials and witnesses also said that Ahmed al-Hashimi, a motorist, had been shot in a residential area of the town.
Residents said dozens of fighters from the Southern Movement were forcing businesses in Daleh to close and motorists to keep off the roads.
Following the sentencing of Saleh on Saturday, hundreds of people protested in Daleh, a centre of frequent anti-government demonstrations, blocking off the main road and burning tyres in the town centre, witnesses said.
Gunmen also fired into the air and vowed revenge against authorities.
Widespread protests have also paralysed al-Habilayn, another southern secessionist stronghold.
Southern Yemen has witnessed mounting violence this year, ranging from separatist ambushes to battles with security forces.
The region, where many residents complain of discrimination in the Sanaa government's allocation of resources, was independent following the 1967 British withdrawal from the port city of Aden until it united with the north in 1990.
The region seceded briefly in 1994, sparking a short-lived civil war that ended with it being overrun by northern troops.