UPDATE 3-Nigerian rebels halt offensive, seek peace talks

* MEND says ceasefire a goodwill gesture for Okah's release

* Government welcomes news, army maintains own ceasefire

* Oil markets take wait-and-see attitude

* Rebels demand military withdraw from parts of Niger Delta

(Adds government comment, paragraphs 11-12)

By Austin Ekeinde

PORT HARCOURT, Nigeria, July 15 (Reuters) - A Nigerian militant group on Wednesday declared a 60-day ceasefire in its offensive against the country's oil industry to provide a chance for peace talks with the government.

The Movement for the Emancipation of the Niger Delta (MEND), whose attacks have cut around 300,000 barrels per day of Nigeria's oil output since May, said its decision was also a goodwill gesture for the release of rebel leader Henry Okah on Monday.

The government welcomed the announcement and the military said it would maintain its own two-month ceasefire.

"We are already reaching out to them for dialogue and I assure them that the president can be trusted," said Timiebi Koripamo Agary, spokeswoman for the presidential committee on amnesty.

At least one militant leader, Soboma George, said his fighters would abide by the MEND ceasefire and seek peace talks.

MEND's announcement had little impact on global oil prices as traders were sceptical that peace could be restored in the Niger Delta after years of conflict.

"Until we see more oil actually coming out of Nigeria, it shouldn't have too much of an impact on Nigerian crude oil prices," said an oil trader with a big European company.

Reflecting the fragility of the ceasefire, MEND threatened on Wednesday to resume its offensive after it said seven navy gunboats were headed to one of its camps. But the military denied any attack plans.