Four armed suspects from north Yemen's Saada region have been detained near the American embassy in Sanaa, authorities said.
"The security services arrested four people, near the American embassy, who were in possession of a bag containing four grenades plus a separate fifth grenade and a Chinese-made assault rifle, 296 bullets and five detonators," the Yemeni interior ministry announced on its website.
The statement, issued late on Tuesday, did not say when the men were arrested.
However, on Wednesday, the defense ministry website quoted a security source as ruling out a planned attack on the American embassy. "The people arrested near the embassy... had no intention of attacking it. They were passing the mission by chance and were detained by a police patrol," the source said, according to AFP.
According to the interior ministry, the gunmen, aged between 20 and 33, also had other military equipment in the minibus and taxi in which they were travelling. This included "a siren like those used for ambulances" and 20 cans of petrol.