Jo Cox, a 41-year-old member of Parliament, has reportedly died after being shot and stabbed in public Thursday morning by a man who reportedly shouted “Britain first” as he attacked her. Cox has publicly supported remaining in the European Union during Brexit, the ongoing debate over whether Great Britain should leave it.

The Guardian reports that an unidentified 52-year-old man has been arrested in the attack, which took place near a library in Birstall, West Yorkshire. Cox had just held a regular weekly open meeting for her constituents. Witnesses said the attacker rushed Cox, stabbed her, then pulled a gun from a bag and shot her at least twice.

NBC reported at 12:20 New York time that Cox has died from her injuries.

Cox tweeted a photo just yesterday of her husband and children taking part in the playful Thames “battle” over Brexit.

Update, 12:52 p.m.:

Prime Minister David Cameron said earlier today, before Cox died of her injuries, that it was “right” that both sides in the Brexit debate had suspended their campaigning. He said he wouldn’t attend a planned rally.

After her death, Cameron extended his condolences to her family:

Labour Leader Jeremy Corbyn issued a statement expressing shock and calling Cox “a dedicated campaigner for social justice and peace.”

Cox speaking in the House of Commons. Screenshot via Storyful