Jiddah, Saudi Arabia ? Saudi Arabia offered Islamic militants a limited amnesty Wednesday, saying their lives would be spared if they surrendered but they would face the “full might” of state wrath if they did not.

The ultimatum, issued in the name of King Fahd, called on militants to turn themselves in within a month — suggesting the kingdom was paving the way for a stepped up campaign against al-Qaida-linked fighters who have shaken the country with a series of deadly attacks.

At the same time, the Saudi foreign minister denounced calls by militant clergy for Saudis to travel to Iraq to join insurgents battling the U.S. military and its Iraqi allies.

Some have said that at least one of the guerrillas who killed and beheaded a South Korean hostage in Iraq this week may be Saudi, since the guerrilla spoke Arabic in what seemed to be a Saudi dialect.

The ultimatum was read by Crown Prince Abdullah, the king’s half brother and the country’s de facto ruler, using some of the fiercest language yet against militants.

Abdullah said the offer was open to anyone who has not yet been “arrested for carrying out terrorist acts.”

“We are opening the door of forgiveness,” the crown prince said. “Islamic law will be applied to everyone who deviated from the path of right and committed a crime in the name of religion.

“We swear by God that nothing will prevent us from striking with our full might, which we derive from relying on God.”

Adel al-Jubeir, foreign adviser to Crown Prince Abdullah, later questioned the use of the word amnesty to characterize Abdullah’s offer, saying he didn’t use it during the speech. He added that the offer shouldn’t be interpreted as trying to broker a deal with terrorists.

Al-Jubeir told the The Associated Press that Saudi authorities have dealt major blows to al-Qaida in the kingdom recently, have support from the Saudi population, and will not let up in their pursuit of terrorists.

Under the form of limited amnesty, only those who committed acts that hurt others would be prosecuted, and no one who turns himself in would face the death penalty.