Updated

Leaders of the anti-government protests that have gripped Ukraine's capital for more than two months say they will seek constitutional changes that will weaken the president's powers.

The changes are expected to be discussed in a Tuesday parliament session that comes as Ukraine's political crisis wades through a stalemate. Protesters are refusing to leave their encampment in downtown Kiev or vacate buildings they occupy, but radicals who clashed violently with police last month are holding to an uneasy truce.

Opposition leader Arseniy Yatsenyuk on Monday said constitutional change would "cancel the dictatorial powers of the president and transfer the right of governing the country to the Ukrainian people."

Justice Minister Olena Lukash said last week that officials were preparing measures for constitutional change, but did not give details.

Another protest leader, Oleh Tyahnybok, said Monday that the opposition also will push in parliament for a blanket amnesty for more than 100 people arrested in the protests. Parliament last week offered amnesty to some on the condition that protesters leave many of the buildings they occupy, but the opposition disdained that move, saying authorities were essentially using the arrested as hostages.

Protesters are also demanding President Viktor Yanukovych's resignation and early elections. Yanukovych, who returned to work Monday after a brief sick leave, has shown no sign of accepting either of those demands. In addition, the issue that set off the protests remains: Yanukovych's shelving in November of an agreement to deepen Ukraine's ties with the European Union.

Violent police actions against demonstrations against that decision galvanized anger over a wide range of grievances against his rule and the protests grew markedly, sometimes attracting crowds of more than 100,000.

Yanukovych backed off the EU deal because of concerns that the bloc was not offering a sufficient cushion for the trade that Ukraine would likely lose with Russia, which wants the country to be part of a Moscow-led trade alliance. After shelving the EU agreement, Yanukovych obtained a $15 billion aid package from Russia, further angering protesters who resent Russia's long dominance of Ukraine.

EU foreign policy chief Catherine Ashton is expected in Ukraine this week. Her spokeswoman, Maja Kocijancic, said Monday that the EU is considering new financial measures to support Ukraine's troubled economy, but that the country's political crisis must be resolved before any assistance can be granted.

U.S. Assistant Secretary of State Victoria Nuland also is to visit Ukraine this week to push for a resolution of the tensions.