(Adds details of EU sanctions discussion, paragraph 4)

By David Brunnstrom

BRUSSELS, Sept 28 (Reuters) - The European Union summoned Myanmar's senior diplomat in Brussels on Friday to warn him of tighter sanctions against the military government unless it ends a bloody crackdown on dissent.

The message was delivered to Myanmar's charge d'affairs Han Thu and would be conveyed on Monday to the country's Association of South East Asian Nations partners, who would be urged to use their influence to end the repression, an EU spokeswoman said.

"We told the charge d'affairs we are looking at a series of options and the behaviour of the regime would very much have an impact on the type of options," said Cristina Gallach, spokeswoman for EU foreign policy chief Javier Solana.

EU experts looked into possible restrictions on exports from Myanmar of timber, precious metals and stones on Friday but did not reach any decisions, one diplomat said. Investments by specific Europeans in the country were not raised, he said.

Separately, Italian Prime Minister Romano Prodi's office said the European Union was discussing backing up a mission to Myanmar by United Nations special envoy, Ibrahim Gambari.

The junta has consented to Gambari's visit and diplomatic sources in Yangon said he was expected on Saturday.

The EU said on Thursday it was urgently looking into a response to the crackdown, including reinforced sanctions.

It has already targeted the military government with visa bans and asset freezes and trade and investment restrictions.

EU officials concede that extending sanctions will have only a limited effect and more important will be efforts to persuade Myanmar's neighbours, especially its main ally China, to bring their influence to bear.

"The visa ban list could be enlarged ... but adding 10 or 20 names to the list will not change dramatically the attitude of the regime, I'm afraid," said an EU official. "More important is peer pressure of countries in the region."

NO TALK OF BOYCOTTS

Activist Mark Farmaner of the Burma Campaign U.K. called the EU sanctions "pathetic". He said the freeze on assets netted less than 7,000 euros in all 27 EU member states and while there was a restriction of access to the EU market, many countries allowed their companies to do business in Myanmar.

France's Total <TOTF.PA> is one of the main foreign investors and according to the Burma Campaign UK its venture earns the military junta hundreds of millions of dollars a year.

On Wednesday, French President Nicolas Sarkozy called for a freeze of investment by French firms in Myanmar.

Total responded by saying no new investment was planned but added that its departure from the country would aggravate the situation as its place would be taken by others who treated their staff less well.

EU officials and diplomats said Total's project had not come up in discussions about the possible extension of sanctions.

On Thursday, the European Parliament called for tougher sanctions on Myanmar and one top lawmaker said EU states should boycott the Beijing Olympics unless China intervenes there.

A spokesman for the European Commission said China would be urged to bring its influence to bear, but added: "We're not talking about boycotts or things like that."

EU exports to Myanmar totalled 83 million euros in 2005, imports from Myanmar stood at 287 million, according to EU data. (Additional reporting by Mark John in Brussels and Silvia Aloisi in Rome)

AlertNet news is provided by