By Orhan Coskun
ANKARA (Reuters) - Prime Minister Tayyip Erdogan described a corruption investigation shaking his government as a "black stain on Turkey's democratic history" on Tuesday and a worse betrayal than any of the military coups of past decades.
Addressing members of his ruling AK Party in parliament, Erdogan said the corruption investigation was being driven by outside forces opposed to Turkey's assertive foreign policy and bent on damaging its economy ahead of elections this year.
He appeared to soften his stance on plans to give government greater control over the naming of judges and prosecutors, saying he would drop the proposals if the opposition agreed instead to changes to the constitution.
But the main opposition CHP, which argues the government's plans violate the constitution, said it would come to the negotiating table only if Erdogan withdrew the proposals first. A senior AK Party official said he was not optimistic of reaching a compromise.
The corruption scandal, one of the biggest challenges of Erdogan's 11-year rule, erupted on December 17 with the detention of dozens of people including businessmen close to the government and three cabinet ministers' sons.
Turkey has been held up by the United States and other Western allies as an example of a working Muslim democracy since Erdogan was first elected in 2002. But a crackdown on popular protests in June and Erdogan's reaction to the corruption scandal have raised doubts about democratic reform.
"December 17 is a black stain on Turkey's democratic history. It has surpassed all previous coup attempts and has been recorded as a betrayal to the state, democracy and the nation," Erdogan said to applause from his party members.
"This operation targeted our national foreign policy, our national will, our national intelligence agency," he said.
The army forced four governments from power in the second half of the 20th century. A 1960 coup resulted in the hanging of the prime minister and two other ministers and subsequent putsches were accompanied by mass arrests, torture and deaths.
Erdogan moved soon after taking office to break the political influence of the army, an achievement welcomed by many at home and abroad as a democratic breakthrough.
Erdogan has responded by purging hundreds of police officers and seeking tighter government control over the judiciary, a feud which has raised alarm in Western capitals and shaken investor confidence in what was long one of the world's fastest growing economies.
He said he was willing to drop a draft bill which would hand the government more control over the High Council of Judges and Prosecutors (HSYK), which makes senior judicial appointments, if the opposition agreed instead to amendments to the constitution.
It was not clear what those changes might be, but the Hurriyet newspaper said the AK Party could propose a modification to an article regulating the structure of the HSYK.
Erdogan's opponents view the draft bill as an effort by the government to stifle the corruption investigations and have said the proposed changes violate the constitution.
"If the opposition says 'let's make a change in the constitution' we're up for that," Erdogan said, adding senior ruling party officials were in talks with the opposition.
"If necessary we will halt the ongoing work on the law."
Parliamentary sources said Justice Minister Bekir Bozdag and another senior AKP official would meet the main opposition Republican People's Party (CHP) to try to find a compromise.
The main opposition CHP, which has said the government's plans violate the constitution, said it would only come to the negotiating table if Erdogan withdrew the proposals first.
"We stand where we were last night," CHP vice chairman Faruk Logoglu told Reuters.
"First they have to withdraw the proposal and that would create a platform for a possible consensus," he said.
President Abdullah Gul, seen as a more conciliatory figure than Erdogan, also discussed the issue with opposition leaders before holding talks with the prime minister late on Monday.
(Additional reporting by Daren Butler in Istanbul and Humeyra Pamuk in Ankara; Writing by Nick Tattersall; editing by Ralph Boulton)