Skype has stepped up its efforts to break into the competitive US VoIP consumer market with the promise of free international calls.

The company today offered its US-based users one hour of free international calling to landline phones in 30 countries.

Under the terms of the offer, which runs until 30 June, US Skype users signing up to the firm's SkypeOut service will be offered 60 minutes of free calls to landlines in Canada, France, Germany, Hong Kong, Italy, Mexico and the UK among others.

The offer comes one month after Skype announced that customers in the US and Canada can make free SkypeOut calls to any landline or mobile phones in the two countries until the end of the year.

Skype users in both countries were previously required to pay for Skype calls from their PCs to traditional telephones.

"With free calling within the US and Canada until the end of the year, and one hour of free international calling until the end of the month, we are making it incredibly convenient for our US Skype users to keep in touch with friends, family and business associates," said Henry Gomez, general manager at Skype North America.