Sena's Punjab President Sanjiv Ghanauli, Chairman Rajiv Tandon and Senior Vice-President Rajesh Palta said that "the sudden stopover in Lahore would embolden Pakistan and send wrong signals globally that India was under pressure vis-a-vis its relations with the neighbouring country."
Sena leaders said that such "objectionable steps raise question on country's image and credibility."
"There is widespread anger against Pakistan in our country, but our PM is having stopover in Lahore to extend birthday greetings to Pakistan PM Nawaz Sharif," they said.
Branding the visit a "duel standard" by the government, the leaders alleged that Modi had taken "U-turn" regarding Pakistan.
"During election, Modi had declared with repeated chest beats that he would talk to Pakistan in the language that it understood, but post-polls he landed in that country which he wanted to teach a lesson," they said.
"His pre-poll regular belligerence and the post-poll abrupt bonhomie vis-a-vis Pakistan is a sad mismatch, indicative of a doublespeak," they remarked.
Asserting that the country had "no compulsion" to improve ties with Pakistan, Sena leaders reminded Modi that "it was the same country which had beheaded our soldiers and taken their heads as trophies, besides engineering Mumbai attack."
They also reminded PM that violations of LoC, infiltrations and cross-border terrorism were going on unabated.
"By keeping everyone in dark about the visit, your gaffe merited an apology to the country," the party leaders added.