ANKARA (Reuters) - Turkey has no choice but to act alone given too little progress has been made with the United States forming a “safe zone” in northeastern Syria, President Tayyip Erdogan said on Tuesday in his most direct indication of a cross-border offensive.

After eight years of war in neighboring Syria, Ankara and NATO ally Washington have agreed to establish a zone along 480 km (300 miles) of the border that Turkey wants to be 30 km deep.

Under the Turkish plan, up to 2 million Syrian refugees would be settled in the area that would be cleared of the Syrian Kurdish YPG militia, which Ankara deems a terrorist organization.

Since agreeing to set up the zone in northern Syria, Turkey has repeatedly warned of unilateral military action if efforts do not meet its expectations, saying it would not tolerate any attempts by Washington to stall the process.

It set an end-September deadline for action.

“We have not achieved any of the results we desired in the east of the Euphrates. Turkey cannot lose even a single day on this issue. There is no other choice but to act on our own,” Erdogan said at the parliament’s opening ceremony in Ankara.

“We plan to settle two million people in the safe zones we will establish. We calculated the costs and we will carry out efforts to improve. We will start taking steps as soon as the region is saved from the invasion of terror,” he said.

While diplomats, analysts and Turkey’s main opposition say Ankara would be unwilling to anger Washington with a military incursion as the allies try to repair strained ties, Erdogan’s comments on Tuesday marked the clearest indication of an offensive in the region.

He added that Turkey aimed to host an “international donors meeting” to get funding for its plans in the area, which he said would stretch from the Euphrates river in Syria east to the Iraqi border.

Erdogan has repeatedly called on Turkey’s allies to provide financial support for the plans, including in his speech at the United Nations last month. But Ankara is unlikely to receive a response for any plan that settles people hundreds of kilometers from their homes and alters the demographics of northeast Syria.