Addressing SYRIZA's central committee on Saturday, Tsipras said that Madrid and Lisbon officials had sided against Athens during negotiations on February 20 that led to a four-month extension of the country's loan deal.

"We were up against an axis of powers led by Spain and Portugal, which for obvious political reasons sought to lead the whole negotiation to the brink," Tsipras said.

"Their plan was, and it remains, to wear down, topple or bring our government to unconditional surrender before our work starts to yield fruit and before the Greek example affects other countries," he said. Both Mediterranean countries will hold elections this year.