The European Central Bank has asked some banks to closely monitor activity on social media to detect a worsening in sentiment which could lead to a deposit run, two banking executives with knowledge of the request told Reuters. European regulators have sharpened scrutiny of banks' liquidity after the collapse of Silicon Valley Bank and Credit Suisse in March last year, the people said, requesting anonymity because the discussions are private. Banks can run into financial trouble if clients rush to pull deposits at the same time.