BEIRUT, Lebanon — Members of the Syrian Parliament issued an open letter to their British counterparts on Thursday, warning them that an international military strike on Syria would recklessly and illegally “plunge secular Syria, and indeed the whole region, into a cataclysm of sectarian mass murder” and inviting them to visit with their own chemical weapons experts to check the conclusions of the United Nations investigators now in the country.

The letter, which the lawmakers asked be read at a British parliamentary session on Thursday on the proposed strike, was in keeping with a Syrian government strategy of stressing what it sees as values and goals it shares with the West, including secularism and fighting terrorism. The letter condemned the chemical attack last week “without reservation,” without repeating the government’s attempts to blame Syrian rebels for it, and promised Parliament’s own investigation.

The document, a copy of which was obtained from a Syrian businessman close to the government, was addressed to the Parliament speaker, John Bercow. “Mr. Bercow received the letter today and responded, saying that he has deposited it in the library of the House of Commons where it can be read by members of Parliament,” said a spokeswoman for the House of Commons, who asked not to be named in line with standard parliamentary policy.

The writers invoked the 1914 assassination that set off World War I and of the invasion of Iraq in 2003, declaring, “Local tragedies become regional wars that explode into global conflict because of breakdowns in communication.”