Police have arrested two more alleged November 17 terrorists, and said Sunday one was believed to be a hit man in four assassinations -- including those of a U.S. Air Force sergeant and a British brigadier.

Police now have a total of nine suspects in custody, including an alleged leader of the November 17 group, which carried out bombings, assassinations and robberies with impunity for 27 years. They are still searching for other November 17 members, believed to number a few dozen.

A magistrate on Sunday began arraigning three of the first suspected November 17 terrorists, arrested after police made their first ever breakthrough against the group following a botched bombing on June 29.

They include two brothers who confessed to nine of the 23 killings attributed to November 17, and family friend charged with a bombing and robbery. Another brother, injured in the failed bombing, remains hospitalized under police guard.

Authorities believe they are now close to dismantling a group which eluded Greek, American and British authorities since 1975, when it appeared with the killing of the CIA station chief in Athens, Richard Welch.

The arrests came as the Sunday edition of the Eleftherotypia newspaper reported that November 17 had been planning to attack a convoy of NATO peacekeepers heading from the northern port of Thessaloniki to Macedonia and Kosovo. NATO uses Thessaloniki as a logistical base for its peacekeeping operations.

Police identified the two men arrested in northern Greece late Saturday as Iraklis Kostaris and Costas Karatsolis, both 36-year-old real estate agents who are close friends.

Police spokesman Lefteris Ekonomou said Kostaris denied involvement, but evidence and statements by others in custody implicate him in several of the group's attacks between 1988 and 2000. They include the killings of Air Force Sgt. Ronald O. Stewart in March 1991 and of British defense attache Brig. Stephen Saunders in June 2000.

Kostaris has also been implicated in two attempted murders and a string of armed robberies.

He allegedly recruited Karatsolis into November 17, Ekonomou said. Karatsolis has confessed to carrying out three armed robberies and participating in the theft of dozens of anti-tank rockets from an army base in central Greece in 1989, Ekonomou said.

Undergoing arraignment Sunday were Christodoulos Xiros, 44, who police say has confessed to nine killings, including those of Stewart and U.S. defense attache Capt. William Nordeen.

His brother Vassilis, 30, has confessed to two assassinations, including Saunders -- November 17's last victim -- and a string of other attacks and robberies, police said.

Both have been charged with multiple counts of murder and attempted murder, bombing attacks, armed robbery and forming a criminal organization. They face life in prison. Greece does not have the death penalty.

Vassilis Xiros' friend Dionissis Georgiadis, 26, has confessed to participating in a bombing and a robbery, according to police.

Of the others in custody, Alexandros Giotopoulos, 58, is believed to be a leading member and founder of the group. He denies being involved, but has been charged with multiple counts of murder and attempted murder.

He is to be arraigned Wednesday along with Vassilis Tzortzatos, 48, who has confessed to taking part in killing eight Greeks and in seven attempted murders.

Another Xiros brother, 40-year-old Savas, remains under police guard in hospital after being injured in the botched June 29 bombing.

His injury provided the clues which helped unravel November 17, leading police to weapons caches and hide-outs. Savas Xiros has not yet been officially arrested or charged, but he is believed to have also been one of the group's executioners.

Authorities are also holding Theologos Psaradelis, 59, who has confessed to an armed robbery and is charged with participating in one more.

Ekonomou repeated a police appeal for any information leading to the arrest of 44-year-old beekeeper Dimitris Koufodinas, who had been living with Savas Xiros' former wife, Angeliki Sotiropoulou. He is believed to be a key November 17 hit man.

Both Sotiropoulou and Savas Xiros' current girlfriend, a Spanish makeup artist, have been questioned and released.