CARACAS, Venezuela (AP) — A birther debate in Venezuela is heating up as President Nicolas Maduro's opponents seek to push the embattled socialist leader from office at any cost.

On Tuesday, the opposition-controlled congress will hold a debate on Maduro's "constitutional situation" in which lawmakers vow to present evidence that he's a dual Colombian citizen and therefore constitutionally ineligible to hold Venezuela's highest office.

Ever since taking office in 2013 Maduro has been beset by unsubstantiated claims that he was born in his mother's native Colombia.

But the birther argument is nonetheless gaining momentum after the opposition last week declared itself in open rebellion over the decision to suspend a recall referendum seeking Maduro's removal.

As lawmakers meet Maduro is expected to address supporters upon his arrival from a tour of the Middle East.