The Guardian website topped 100 million monthly browsers for the first time in March, when stories including the search for the missing Malaysia Airways jet helped boost online traffic for most UK national newspapers.

Boosted by a 12% month-on-month traffic surge, theguardian.com website network – which includes MediaGuardian – hit a new record of 102.3 million monthly unique browsers in March.

Average daily unique browsers also reached a new high of 5.67 million, up 5% month-on-month, according to the latest Audit Bureau of Circulations multiplatform figures published on Thursday.

David Pemsel, deputy chief executive of Guardian News & Media, said: "Our strong performance in Australia is especially encouraging less than a year since our launch there, while the announcement this week of Guardian US winning a prestigious Pulitzer prize underlines our influential position in the US media landscape.

"100 million browsers is an historic landmark for everyone at the Guardian – but we won't rest on our laurels. We'll continue to innovate editorially, digitally and commercially in order to break new ground and attract still more readers to our world-class, independent, open journalism."

Theguardian.com is the second UK newspaper website to top 100 million monthly browsers. Mail Online passed the milestone during the London Olympics month, August 2012.

The Associated Newspapers website remains by some distance the UK's most popular digital newspaper operation, returning to traffic growth in March after a dip in February.

Mail Online reported an 8% increase in monthly unique browsers to 179.8 million, while average daily uniques rose very slightly – 0.22% – to 11.27 million.

Mirror Group Nationals, which includes Mirror.co.uk, also passed a significant traffic milestone in March, topping 50 million monthly uniques (up 8.4% month-on-month to 51.1 million) and 2.5 million average daily uniques (up 2.5% to 2.52 million) for the first time.

Independent.co.uk's monthly browsers surged 24% compared to February to just under 37 million last month, while daily average uniques jumped nearly 16% to 1.65 million.

Telegraph.co.uk also had a good month, increasing monthly browsers nearly 21% to 72.2 million and average daily browsers by 12.6% to 3.6 million.

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