U.N. Secretary-General Ban Ki-moon says he expects Lebanon to cooperate with a U.N.-backed tribunal investigating the 2005 assassination of former Lebanese Prime Minister Rafik Hariri. The tribunal has issued indictments and arrest warrants for four suspects in the case.

Mr. Ban called on all states to support the work of the joint international and Lebanese court based in The Hague. It submitted the indictments and arrest warrants to Lebanese prosecutor general Saeed Mirza on Thursday without disclosing the names of those charged.

Lebanese officials told Western news agencies that at least two of the four individuals are members of the Iranian-backed Hezbollah militant group.

Hezbollah dominates the new Lebanese government formed earlier this month by Prime Minister Najib Mikati. The group's Al-Manar television station responded to the indictments by dismissing the tribunal as “politicized.”

Hezbollah has denied any involvement in Mr. Hariri's killing and has threatened to “cut off the hand” of anyone who tries to arrest its members in the case.

Rafik Hariri's son, former prime minister Saad Hariri, says the arrest warrants represent a “historic moment” for Lebanon. He urged Mr. Mikati's government to cooperate with the tribunal.

U.S. State Department spokesman Mark Toner said the indictments are an “important step toward justice and ending impunity for political assassinations” in Lebanon.

Mr. Mikati's cabinet says it is committed to finding the truth behind the Hariri assassination and will monitor the tribunal's progress while trying to prevent threats to Lebanon's stability.

The tribunal can order the indictments to be published in local media if the Lebanese government does not arrest the suspects within 30 days.

In January, Lebanon's president appointed Mr. Mikati as prime minister to replace Saad Hariri. Mr. Hariri's unity government collapsed that month after Hezbollah quit in protest of the tribunal's investigation.

Mr. Mikati formed his coalition government on June 13 after months of negotiations. Hezbollah and its allies hold a majority of seats in the 30-member Cabinet.