Yemeni security forces have detained three suspected of links to an attack that killed a top military commander last week, a security source said yesterday. Yemeni forces have stepped up security across the country since a suicide bomber killed Major General Salem Qatan, the commander of military forces in southern Yemen, on Monday.

A Yemeni security source said Sami Dayyan, who they believe is a local insurgent leader, was captured along with two other suspected militants while travelling to Lahej province from the port city of Aden.

The source said that explosives and suicide belts were found in the vehicle, which was stopped for a routine search outside Aden on Thursday evening. The three men were being questioned. “They were in the process of preparing for operations similar to the one that killed Qatan,” the source said.

The men had “entered Aden in previous days to prepare for the operation in which Qatan was assassinated,” he said. The Yemeni Defence Ministry confirmed the arrest in a statement sent over mobile telephones and described Dayyan as “a prominent leader”.

Qatan’s death highlighted the tenuous grip of Yemen’s central authorities on the south despite weeks of campaign to crush the militants. Residents of the al-Mansoura district of Aden said they had spotted Dayyan looking to rent a house in the neighbourhood a few days ago and chased him away.

In a separate incident, activists in a group calling for the secession of southern Yemen said yesterday that security forces shot and killed two young men in Aden during a march following the funeral of another man who was killed by a sniper on Wednesday.

They said paramilitary policemen guarding a square that had recently been cleared of protesters opened fire on the marchers when they approached. One young man was killed on the spot while the other died in hospital, they said.