Police negotiating with London City Airport protesters

Police cars parked outside London City Airport, Tuesday, Sept. 6, 2016. All flights in and out of London City Airport were disrupted on Tuesday after demonstrators blocked a runway to protest expansion plans.The protest ended after police arrested nine people on suspicion of aggravated trespass. (AP Photo/Kirsty Wigglesworth) (The Associated Press)

Police cars parked outside London City Airport, Tuesday, Sept. 6, 2016. All flights in and out of London City Airport were disrupted on Tuesday after demonstrators blocked a runway to protest expansion plans.The protest ended after police arrested nine people on suspicion of aggravated trespass. (AP Photo/Kirsty Wigglesworth) (The Associated Press)

All flights in and out of London City Airport have been disrupted after demonstrators blocked a runway to protest expansion plans.

Police say they are negotiating with nine protesters who managed to get airside at about 5:40 a.m. (0440 GMT; 11:40 p.m. EST Monday) Tuesday. The demonstrators erected a tripod and locked themselves together.

The group Black Lives Matter claimed responsibility on social media. It says expansion consigns the local community of Newham to environmental degradation.

The group says the airport caters to people working in financial services — making it a facility to help the wealthy.

Black Lives Matter says "when black people in Britain are 28 percent more likely to be exposed to air pollution than their white counterparts, we know that environmental inequality is a racist crisis."