Leaders are entering the final day of talks at the G20 meeting in Hamburg as officials try to bridge the gap with the US on issues such as trade and climate change.
German Chancellor Angela Merkel, who is hosting the summit in Hamburg, said the talks so far had been "very difficult".
Negotiators worked through the night in an attempt to reach a compromise on the wording of the final summit statement.
It comes after a second night of violent protests on Hamburg's streets.
The G20 (Group of Twenty) is a summit for 19 countries, both developed and developing, plus the EU.
Leaders at the summit are struggling to find common ground with the US following President Donald Trump's decision to withdraw from the Paris climate agreement last month.
One unresolved section of the G20 communique is linked to the US desire to have a reference to fossil fuels - according to reports quoting unnamed EU officials.
A separate issue is Trump's rejection of free trade - although the president has said that he is not opposed to trade in principle, his position is that any trade deals agreed have to protect US industry.