Riot police in Gdansk, armed with rubber truncheons, broke up a march of about 5,000 Solidarity supporters marking the seventh anniversary of Poland's outlawed trade union. No injuries or arrests were reported. Meanwhile, in Wroclaw, police dispersed an anniversary rally of about 500 union supporters and arrested 10 people, an opposition spokeswoman said. In Krakow, several hundred people held a similar rally without incident, while in Poznan, 1,500 Solidarity supporters attended a special Mass. Earlier, police only watched as Solidarity leader Lech Walesa laid flowers at a Gdansk monument to honor workers killed in anti-government riots in 1970.