ISTANBUL (Reuters) - Iran is using Iraqi airspace to fly supplies to Syrian President Bashar al-Assad's forces and thousands of Iraqi militia fighters have crossed into Syria to support his troops, Iraq's fugitive vice president said on Sunday.
Tareq al-Hashemi, who fled Iraq in December and was sentenced to death a week ago by an Iraqi court, said the government of Prime Minister Nuri al-Maliki was failing to stop ammunitions and armaments reaching Assad's forces.
"My country is unfortunately becoming an Iranian corridor to support the autocratic regime of Bashar al-Assad, there is no doubt about that," Hashemi told Reuters in an interview in Istanbul.
"It is not only the airspace. It is thousands of militia now inside Syria, supporting Bashar al-Assad and killing Syrian innocent people," he said, citing reports he had received from Iraq's Anbar province, which borders Syria, and from members of the Syrian opposition.
He said Iraqi militia fighters had been detained inside Syria by members of the Syrian opposition.
A senior adviser to Maliki rejected the accusations, saying Iraq was committed to not siding with any party in the Syrian conflict.
"The prime minister ... is always confirming that Iraq will not allow any state to use its airspace to transport arms to Syria," said Ali al-Moussawi, Maliki's media adviser.
Hashemi, a senior Sunni Muslim politician and fierce critic of Maliki, a Shi'ite, fled Iraq after the authorities issued a warrant for his arrest in December, a step that risked shredding a fragile power-sharing agreement among Shi'ite, Sunni and Kurdish blocs.
An Iraqi court sentenced him to death by hanging last Sunday after a trial on charges that he ran death squads. Hashemi says the case is politically motivated and is built on testimony extracted under torture.
Although Maliki's government has said it backs neither side in the Syrian conflict, Iraqi Shi'ite leaders fear that if Assad falls, Syria would splinter along sectarian lines and this would bring about the rise of a hardline Sunni government likely to upset Iraq's fragile security and Shi'ite-Sunni mix.
Assad's forces have been battling out-gunned but increasingly effective rebel fighters seeking his overthrow in Syria for the past 18 months, an uprising in which activists say 27,000 people have been killed.
The mainly Sunni Muslim rebels are supported by Gulf Arab states and neighbouring Turkey in their struggle to topple Assad, whose minority Alawite faith is an offshoot of Shi'ite Islam. Shi'ite Iran has been Assad's staunchest ally.
The commander of Iran's Islamic Revolutionary Guards Corps (IRGC) said on Sunday IRGC members were providing non-military assistance in Syria and Iran may get involved militarily if its closest ally comes under attack.
Western countries and Syrian opposition groups have long suspected Iran has troops in Syria. Iran has denied this.
Hashemi said Iraq had been allowing Iran to get around U.S.-led economic sanctions aimed at forcing the Islamic Republic to give up its nuclear programme.
He said Iranians, faced with a sharp deterioration of the rial, were using banks in Iraq to buy U.S. dollars which they then smuggled back into Iran. He said Iraq's government had also failed to enforce sanctions against Syria.
"It is not only prolonging the life of Assad's regime but at the same time deepening the poverty of Iraq, because we are still in need of (every) single U.S. dollar," he said.
Hashemi's accusations raise questions about the extent of U.S. influence in Baghdad, nine months after U.S. troops left.
President Barack Obama withdrew the last U.S. troops in December, after almost nine years of war. Critics say the move has diminished U.S. influence in Baghdad despite massive investment in the country.
Maliki's government has said it wants good relations with the United States, but also has close ties with U.S. foe Iran.
The sentence against Hashemi threatened to stoke sectarian tension in Iraq, whose Shi'ite-led government is battling political instability and a Sunni Islamist insurgency.
Hashemi said his trial was symptomatic of the injustice, corruption, abuse of human rights and growing sectarianism plaguing Iraq under Maliki.
"I see my country drifting from democracy to some sort of tyrannical regime ... We do now have one single major stumbling block, which is the prime minister," he said.
He said he was working with his lawyers on a legal challenge to the sentence against him and hoped Iraqi President Jalal Talabani would intervene "to uphold the constitution".
He had also written to U.N. Secretary General Ban Ki-moon and was ready to face the accusations against him anywhere he could be guaranteed a fair trial, he said.
Additional reporting by Ahmed Rasheed in Baghdad, Marcus George in Dubai; Writing by Nick Tattersall; Editing by Janet Lawrence