Relations between Pakistan and Bangladesh have been strained since the 1971 independence war in which Bangladeshi nationalists broke away from what was then West Pakistan. Around 3 million people lost their lives during Bangladesh's fight for independence.

But this month, Pakistanis and Bangladeshis witnessed an unprecedented move between the leaders of the two countries.

Last Friday, Pakistani Prime Minister Imran Khan congratulated Bangladeshi Prime Minister Sheikh Hasina on her country's 50th anniversary of independence, inviting her to Pakistan for a visit.

"On my own behalf, and on behalf of the government and people of Pakistan, I have the great pleasure in extending our felicitations on the 50th anniversary of the People's Republic of Bangladesh," Khan wrote in a letter, which has been hailed as an attempt to bring Islamabad and Dhaka closer together.

Also last week, Sheikh Hasina sent a letter of congratulations to Khan on Pakistan Republic Day, which marks the Lahore Resolution. The resolution, also known as the Pakistan Resolution, was passed on March 23, 1940 and celebrates a major milestone in Pakistan's struggle to become an independent state.

Calls to Pakistan to issue apology

The legacy of Bangladesh's independence war has tainted relations between the two Muslim-majority South Asian countries for years.

Author Anam Zakaria commended the recent reconciliation efforts by both the Pakistani and Bangladeshi governments, but stressed that if either country wants to make any "meaningful strides," Pakistan must "acknowledge the violence of 1971 as well as the political, economic and cultural discrimination prior to Bangladesh's birth."

According to Zakaria, "owning up to the past" and issuing a formal apology for war crimes committed in 1971 will allow the two countries to "deepen" diplomatic and economic relations.

"Half a century later, Pakistan has not owned its past. Textbooks, museum exhibits and mainstream narratives continue to distort and erase history and a selective remembering and forgetting of the past has been institutionalized by the state," she told DW.

"The denial and minimizing of violence 50 years on is deeply painful for Bangladeshi survivors and their families. Pakistan's acknowledgement is critical…Nations cannot simply erase their history and move on. Our past will continue to haunt our present unless we engage deeply and learn from it," she added.

For Ali Riaz, a political science professor at Illinois State University, recent engagements between Dhaka and Islamabad may be described as "ice-breaking" but that real progress also "hinges on Pakistan's unconditional apology for the 1971 war."

"A better relationship requires Pakistan's initiative to address the 1971 war, especially the genocide perpetrated by the army," he said. "Unconditional public apology from Pakistan is long overdue … No nation can move forward without confronting its dark past."

However, Michael Kugelman, a South Asia expert at the Washington-based Woodrow Wilson Center for Scholars, doesn't feels optimistic about the current state of political affairs between the two countries.

"This is a very complex and sensitive issue …I suspect that bilateral relations would have to be in a far better place than they are now in order for Islamabad to believe it has the political space to take such a major step," he said.

The relationship between Dhaka and Islamabad seemed bleak in recent years. In 2016, a row over the execution of an Islamist leader in Bangladesh led to an all-out diplomatic spat between the two countries, with both sides summoning each other's ambassadors.

Pakistan said the country was "deeply saddened" by the execution of top Islamist party leader Mir Quasem Ali for suspected war crimes, prompting Dhaka to accuse Islamabad of interfering in its internal affairs.

Small steps toward strengthening ties, economic cooperation

But Riaz thinks Khan's decision to congratulate Bangladesh on its golden jubilee of independence last week indicates a willingness to restrengthen ties.

"In recent months, overtures from both countries indicate that they are trying to set aside their differences of the past decade. A telephone call from the Pakistani prime minister to his Bangladeshi counterpart last summer, for example, indicated that Pakistan is interested in turning the page," Riaz told DW.

"The Bangladesh government has appropriately reciprocated in recent months … these are positive signs," Riaz said.

Bangladesh and Pakistan both indicate "a willingness to strengthen relations," Kugelman told DW, adding that Pakistan has been turning to its neighbors in the hopes of increased regional interconnectivity and economic activity.

"For Islamabad, there is a motivation to increase ties with more of its neighbors to promote greater commercial cooperation — part of an intended broader Pakistani foreign policy reset meant to focus more on economic relations," he said.

Looking to the future, Kugelman said there is scope to increase trade.

"Economic cooperation is a logical space for stepped-up collaboration. It's a relatively safe space that can help build trust and goodwill for deeper cooperation in other areas," he said.

Kugelman said that although Bangladesh-India relations having grown considerably under Indian Prime Minister Narendra Modi, there have been some setbacks over New Delhi's policies that some in Bangladesh consider to be discriminatory against Muslims.

"This gives Pakistan another opening, to try to capitalize on these tensions and strengthen its relations with Bangladesh," he added.