US President Donald Trump said that a pipeline project has made Germany captive to Russia.

US President Donald Trump during a combative breakfast that kicked off what was already expected to be a fraught NATO summit said that a pipeline project has made Germany "totally controlled" by and "captive to Russia".

US President, in a testy exchange with NATO secretary-general Jens Stoltenberg, took issue with the US protecting Germany when the European nation is making deals with Russia.

Trump appeared to be referring to the Nord Stream 2 pipeline that would bring gas from Russia to Germany's north-eastern Baltic coast.

US President later said, "Germany as far, as I'm concerned, is captive to Russia" and urged NATO to look into the issue.

Trump was expected to see German Chancellor Angela Merkel later in the day.

Stoltenberg pushed back, stressing NATO members have been able to work together despite their differences.

The dramatic exchange set the tone for what was already expected to be a tense day of meetings with leaders of the military alliance.

Trump, in a message to Germany, asked why the US should "protect you against Russia" when the two countries were making deals.

The leaders of 29 NATO Allies and many partner nations will take decisions to strengthen NATO’s deterrence and defence in Brussels on Wednesday and Thursday (11 and 12 July 2018).