London (CNN Business)The London Stock Exchange (LDNXF) is investigating an issue that is preventing some stocks from trading.

The exchange said in a statement Friday that the opening of the FTSE 100 and FTSE 250 indexes had been delayed.

Barclays (BCS), BP (BP), HSBC (HSBC) and Rio Tinto (RIO) are among the companies that make up the FTSE 100.

The exchange said it was investigating a “potential trading services issue” but additional details were not provided.

    London’s stock market previously suffered a technical glitch in June 2018 that delayed the start of trading by one hour.

    This is a developing story …