Experts from the IMF and the EU are scrutinising a list of economic reforms proposed by Athens in a bid to unlock another €7.2 billion ($7.8 billion) in loans to stave off possible bankruptcy.
Greece says the reforms would help raise an extra three billion euros for government coffers without resorting to wage and pension cuts.
"The process of assessment of this plan is very complex and I don't foresee any breakthrough before Easter," Tusk said.
Easter this year falls on Sunday, April 5th.
"I think that today we can say that the (economic) situation in Greece is under control," he told a news conference with Spanish Prime Minister Mariano Rajoy.
"I hope we will reach an agreement by the end of April, for me it is possible."
In April, Athens needs to roll over 2.4 billion euros in short-term debt and repay another €820 million, including €460 million to the International Monetary Fund.
A defiant Greek Prime Minister Alexis Tsipras told lawmakers late on Monday he wanted a deal but would not submit to creditors unconditionally.
He swept to power after January elections on a pledge to end the austerity measures imposed as part of a massive bailout by Greece's creditors, which Athens blames for hammering the economy.
Rajoy reiterated his hope that the negotiations on a new debt deal would be successful and that Greece would remain in the eurozone.
Greece "must understand that for the European Union it is very important that the message that is sent is that the rules of the game must be respected," said Rajoy, who has been accused by Athens of taking a hard line on Greece.