(Adds details)

GAZA, July 10 (Reuters) - Hamas arrested two militants who fired cross-border rockets into southern Israel from the Gaza Strip on Thursday, in the first such detentions since the Islamists and Israel agreed a truce last month, militants said.

An official with the al-Aqsa Martyrs Brigades, a militant faction of Palestinian President Mahmoud Abbas's Fatah movement, said Hamas security forces arrested two of its members who were involved in firing two rockets at Israel.

"They chased the two after they fired the rockets and abducted them," the official said.

Hamas, which seized control of the Gaza Strip after routing Abbas's more secular Fatah faction a year ago, had no immediate comment.

Al-Aqsa said it fired the two rockets into southern Israel after Israel's killing of an unarmed infiltrator from the coastal area earlier in the day.

The Egyptian-brokered truce, which took effect June 19, has been shaken by several rocket attacks, prompting Israel to temporarily close the Gaza Strip's border crossings.

AlertNet news is provided by