UPDATE 1-Niger lawyers to strike, EU delays aid over vote row

* Niger lawyers to strike over referendum row

* European Commission to delay budget support

* Tandja launches "Yes" campaign, warns against chaos

(Adds Tandja's address to the nation)

By Abdoulaye Massalatchi

NIAMEY, July 12 (Reuters) - Niger's lawyers said on Sunday they would strike this week in protest at the president's plan to hold a referendum on extending his rule, a day after the European Union delayed an aid payment over the vote row.

Despite mounting opposition at home and abroad, President Mamadou Tandja is pushing ahead with an Aug. 4 vote to allow him to hold on to power for another three years in the uranium producing country after his second term expires in December.

"The General Assembly of the Order of Lawyers has decided to lay down its robes and not work on Monday, July 13, 2009 in solidarity with the Constitutional Court," the lawyers said in a statement referring to Niger's top court.

The court was dissolved last month after it declared Tandja's plans illegal. The president has also dissolved parliament, assumed emergency powers and imposed restrictions on the private press in his bid to hold the poll.