The government said the operations against men linked to former Prime Minister Gulbuddin Hekmatyar thwarted the greatest threat yet to Hamid Karzai's interim administration. But the arrests are also likely to inflame tension between Hekmatyar's largely Pashtun followers and the northern alliance, which is dominated by ethnic Tajiks and controls key ministries.
"They wanted to launch a coup d'etat against the government," said Mohammed Naseer, security director at the Kabul governor's office. He said the plotters also wanted to disrupt the loya jirga, a political gathering planned for June to select a new government.
Afghan authorities said the plot included plans to kill Karzai and ex-King Zahir Shah in a campaign of bombings also directed against U.S. troops and international peacekeepers.
Interior Minister Yunis Qanuni said 300 people were initially arrested in Kabul over the last two or three days and 160 were still in custody and being questioned about their role in the alleged plot.
Kabul police chief General Deen Mohammad Jurat told Reuters that Hekmatyar, head of Hezb-e-Islami, a radical Islamic group once supported by the United States, was behind the plot.
Qanuni confirmed the majority of people arrested were Hezb-e-Islami members and told a news conference the plotters had planned a campaign of "terror, abduction and sabotage."
"There was a series of (assassination) plots against some prominent people including Karzai and the returning King Zahir," Qanuni said.
In Pakistan, a senior leader of Hezb-e-Islami, Qutbuddin Hilal, said those arrested were former - not current - members of the group.
Pashtun leaders may interpret the arrests as an attempt to stifle their moves toward Pashtun unity in advance of the loya jirga, but Qanooni said nobody was arrested "on the basis of political disagreement."
When asked if the majority of those arrested were Pashtuns, Qanooni said only: "Let's not turn it into an ethnic issue."
Lt. Col. Neal Peckham, spokesman for the international peacekeeping force, said weapons had been found and that those arrested also included Pakistani members of another militant group, the Jamaat-e-Islami, a Pakistan Islamic organization with close ties to Hekmatyar. He said the peacekeepers were not involved in the operations, but had been tipped off beforehand.
Afghan police on Monday raided the home of Hekmatyar's one-time aide, Wahidullah Sabaoon, but there was confusion Thursday over his whereabouts. Jurat and Naseer said Sabaoon was among those arrested in the sweep, but Peckham said he was still at large.
Sabaoon was once the military chief of Hezb-e-Islami and served as Afghanistan's defense minister in 1995, when Hekmatyar became prime minister under President Burhanuddin Rabbani. When the Taliban took over in 1996, Sabaoon allied himself with the northern alliance, becoming finance minister for the goverment-in-exile.
Hekmatyar has been a vocal opponent of Prime Minister Karzai and of U.S. presence on Afghan soil, but last month his deputy, Jumma Khan Hamdard, said the party was ready to cooperate with the interim administration.
Power struggles among Hekmatyar's forces and northern alliance factions devastated much of Kabul in the early 1990s, with 50,000 people, mostly civilians, killed, according to the International Red Cross.
Hekmatyar fled to Iran after the Taliban took the capital in 1996, although the Iranian government recently closed his offices in Tehran and his whereabouts are unknown.
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