Ukraine's president Viktor Yanukovych is to return to work tomorrow after a short sick leave.
The announcement last Thursday that Mr Yanukovych was on sick leave due to an acute respiratory illness raised concerns that he may have been taking himself out of action in preparation for declaring a state of emergency as the country's political crisis heads into its third month.
Protesters seeking Mr Yanukovych's resignation held one of their largest gatherings in recent weeks today, with about 30,000 people assembling at the main protest site in Kiev's central square.
The protests began after Mr Yanukovych in late November backed away from a long-awaited agreement to deepen ties with the European Union. They quickly grew to encompass a wide range of grievances after police violently dispersed some of the early gatherings.
During Mr Yanukovych's sick leave, a sense of stasis set in and neither side showed signs of movement. But his return to work could bring new actions.
Top opposition figures spoke at today's rally to urge supporters to push forward with their demands. Arseniy Yatsenkyuk, one of the protest leaders, emphasised the importance of obtaining the release of all people arrested during the protests.
"We must free all," Mr Yatsenyuk said, adding that there were 116 people being held. "Freedom to every hero."
Mr Yanukovych's sick leave was announced the morning after the parliament voted to offer amnesty to many of those arrested during protests, if demonstrators vacated some of the buildings they occupy in Kiev and government buildings elsewhere in the country.
The measure was greeted with disdain by protesters, who characterised it as the government essentially taking hostages and then using them to try to negotiate concessions. The city hall in Kiev, which protesters have seized, is being used as an operations centre and dormitory that is key to supporting the extensive protester tent camp on the nearby Independence Square.
The parliament on Tuesday is expected to consider reforms to the constitution that would reduce some presidential powers and allot them to the prime minister. Mr Yanukovych last week accepted the resignation of Prime Minister Mykola Azarov but has not appointed a new one.