Greek Prime Minister George Papandreou canceled a scheduled trip to the United States on Saturday due to the "uncertain climate" over the debt crisis, according to Greek officials.

The Greek prime minister had left Athens on Friday and was in London when he decided to return to Greece instead of continuing the trip to participate in the UN General Assembly and hold a series of meetings with International Monetary Fund officials.

"The prime minister decided to postpone the trip, since the coming week will be critical for the implementation of the July 21 decisions," said a press release issued by his office.

"The decision was made due to the uncertain international environment and divided opinions within the European countries," Greek government spokesman Elias Mossialos told a local television.

He stressed that Athens "does not wish to offer excuses to anyone to play games with the country's future," announcing that on Sunday Papandreou will chair a cabinet meeting.

"There is no imminent danger in the horizon nor an urgent financial event. But it is time to make serious, final and comprehensive decisions and take all necessary initiatives that will lead to an exit from the crisis," said Greek Deputy Prime Minister and Finance Minister Evangelos Venizelos in a statement Saturday evening while commenting on the change in Papandreou's travel plans.

Venizelos dismissed once again as "irresponsible and ridiculous" scenarios of a coming Greek bankruptcy, denouncing "a systematic speculative attack against Greece and the eurozone by a part of the international markets."

A tele-conference Papandreou held last week with German Chancellor Angela Merkel and French President Nicolas Sarkozy had boosted hope for supports of European leaders to tackle the crisis.

But a eurozone meeting held in Poland on Friday ended in differences among member countries, fuelling anxiety over the debt crisis again.