(ANSA) - BERLIN - Just over a week ahead of a key Eurogroup on Athens' fate, Standard and Poor's downgraded Greece's credit rating again, dropping long and short-term sovereign credit ratings to CCC+/C from B-/B with a negative outlook. Meanwhile Berlin said that an upcoming summit scheduled on April 24 will not make it possible to allocate aid for the Tsipras government.

The ministry of Wolfgang Schaeuble warned that expecting such a step was wrong given the process is quite complex even if a wished-for agreement on reforms is reached.

According to the weekly Die Zeit, the government of Angela Merkel is reportedly working on a plan ensuring that if Greece became insolvent it would not necessarily leave the single currency - allegations which the government has denied.

The fact that lack of confidence dominates - as alleged by European sources who have hinted Eurogroup talks in Riga on the 24th could fail, as reported for example by Sueddeutsche Zeitung - is confirmed by the new downgrade by S&P.

There is also pressure on Premier Alexis Tsipras from the IMF, through the head of economic and monetary affairs department Lose Vinals, who stressed that a Grexit ''would be terrible'' for the population. Meanwhile Mario Draghi in Frankfurt warned that liquidity for Greece has no expiry date though everything depends on the decisions taken by the Greek cabinet.

In Berlin, instead, there is an effort to downplay the alarm while keeping a firm hand. The alleged plan reported by Zeit, according to which the government is working on the possibility of keeping Greece in the euro also in the event of bankruptcy, bailing out banks, is slammed as ''one of many speculations at the moment''. The finance ministry has denied the report.

However, imagining a payment at the end of April is misleading. ''If someone imagines it is possible to pay in April, I think they are wrong'', said a spokesman for the German finance ministry. After the talks, he explained, it will be necessary to reach a ''staff-level agreement to formally change conditions of the aid program''. ''And nobody in the Eurogroup thinks it can be closed on April 24'', he added. The next step is implementing reforms: ''This means Greece needs to approve laws''. There will then be an ''implementation review and, only based on that, a payment will be possible''. (ANSA).