Spy agency tweet adds to US-China protocol spat

A United States spy agency on Sunday apologised for a sarcastic tweet aimed at China over its treatment of American reporters who had travelled with President Barack Obama to cover the G20 meeting there.

"Classy as always China," the Defense Intelligence Agency tweeted on Saturday from its @DefenseIntel account.

"Earlier today, a tweet regarding a news article was mistakenly posted from this account & does not represent the views of DIA. We apologise," CNN quoted the Pentagon-housed spy agency on Sunday as saying in a tweet.

The initial tweet, which has since been deleted, included a link to a New York Times report about a dust-up over security protocols at the tarmac when Obama landed in China -- and later, shouting matches between Chinese officials and Secret Service agents at the West Lake State House, where Obama met Chinese President Xi Jinping, CNN added.

The tiffs were largely over American journalists' access to Obama. Chinese officials unexpectedly limited reporters' access to the President.

When asked about the airport kerfuffle, Obama acknowledged to reporters that "the seams are showing a little more than usual in terms of some of the negotiations and jostling that takes place behind the scenes".

"I wouldn't over-crank the significance of it, because, as I said, this is not the first time that these things happened," Obama said.

"And it doesn't just happen here. It happens in a lot of places, including, by the way, sometimes, our allies. Part of it is we also have a much bigger footprint than a lot of other countries. And we've got a lot of planes and a lot of helicopters and a lot of cars and a lot of guys, and if you're a host country, sometimes it may feel a little bit much."