Sri Lanka said Tuesday it had rejected a US request to send troops to Afghanistan but retracted the claim within hours, triggering angry responses on social media about the government's credibility.

"President Mahinda Rajapakse has rejected a call by US to send Lankan troops to Afghanistan," the government's information department said in an SMS news alert which was immediately rebroadcast by almost all local media outlets.

US diplomats in Colombo appeared puzzled over the Sri Lankan government claim and privately said that there was no pending request.

A couple of hours later, presidential spokesman Mohan Samaranayake officially trashed the government's own claim.

"President Rajapakse has neither received nor rejected any requests by the US for Lankan troops to be sent to Afghanistan," he said in a brief one-paragraph statement.

President Rajapakse's own twitter account @PresRajapaksa admonished journalists to "double check facts w/multiple sources" before publishing and this drew sharp responses from Sri Lankan reporters.

"Are u saying we cant even 'TRUST' what the Govt. Info is saying through its SMS service. Who can we trust?," tweeted Gandhya Senanayake.

"So MR (Mahinda Rajapakse) wants us to verify official Gov info statements as well," tweeted Azzam Ameen. "Journalists blamed not the Govt Info dept who created the blunder."

"How can the government information department make such a blunder. We have published the story on ______. Darn," said another Sri Lankan reporter.

Leaked US embassy cables had shown that Colombo expressed willingness to send troops to train Afghan forces in March 2009. It later changed its mind, fearing possible reprisals from foreign Islamic militants.

Relations between Sri Lanka and the US have been strained as Washington pressed Colombo to probe alleged war crimes by its troops while crushing Tamil separatists in May 2009.